Appendix A.

Source Notes and Explanations

General Notes

POPULATION

Population estimates. The Census Bureau develops estimates with a demographic procedure called a "component change" method. A major assumption underlying this approach is that the components that constitute population change can be represented by administrative data in a statistical model. In order to build the model, Census Bureau demographers estimated each component of population change separately. For the population residing in households, the components of change are births, deaths, and net migration, including net immigration from abroad. For the nonhousehold population, change is represented by net change in the population in group quarters. To develop population estimates, the Census Bureau uses a component change procedure called the Tax Return method (formerly called the Administrative Records method). Each component in the model is represented with data that are symptomatic of some aspect of population change. For example, birth certificates are symptomatic of additions to the population resulting from births; therefore, these data are used to estimate the birth component for a state.

The estimates used as a base for data and the annual changes implied by the figures are subject to estimation error. Variations from actual population levels are inherent in the estimating procedures, stemming from the fact that the correlation between the data series and population is not perfect. The data series being used to reflect population change are all affected to some degree by factors other than population movements and, in addition, are part of reporting systems that are subject to administrative alteration.

Population data for 1997 and revised population data for 1990 through 1996 were released in late December of 1997 for states and mid-March of 1998 for counties. These population data were processed and used in Tables A-1, B-1, and C-1 of this publication. Population figures used to

calculate rates or describe various population characteristics (e.g., race) in table sets A through C, as well as those in Table D, are those released in the previous annual cycle.

Decennial censuses. The population statistics for 1980 and 1990 are based on results from the censuses of population and housing, conducted by the Bureau of the Census as of April 1 in each of those years. As provided by Article 1, Section 2, of the U.S. Constitution, adopted in 1787, a census has been taken every 10 years commencing with 1790. The original purposes of the census were to apportion the seats in the U.S. House of Representatives based on the population of each state and to derive an equitable tax on each state for the payment of the Revolutionary War debt. Through the years, the nation's needs and interests have become more complex, and the content of the decennial census has changed accordingly. Presently, census data not only are used to apportion seats in the House and to aid legislators in the realignment of legislative district boundaries but also are used in the distribution of billions of federal dollars each year. These data are vital to state and local governments and to private firms for such functions as market analysis, site selection, and environmental impact studies. Persons enumerated in the census were counted as inhabitants of their usual place of residence, which generally means the place where a person lives and sleeps most of the time. This place is not necessarily the same as the legal residence, voting residence, or domicile. In the vast majority of cases, however, the use of these different bases of classification would produce substantially the same statistics, although appreciable differences may exist for a few areas.

The implementation of this usual-residence practice has resulted in the establishment of residence rules for certain categories of persons whose usual place of residence is not immediately apparent (e.g., college students were counted at their college residence). As in the above example, persons were not always counted as residents of the place where they happened to be staying on census day. However, persons without a usual place of residence were counted where they were enumerated.

planning, and procedures used for the 1990 Census of Population and Housing, as well as a facsimile of the questionnaires and descriptions of the data products resulting from the census, see U.S. Bureau of the Census, 1990 Census of Population and Housing Guide, Part A, Text (CPH-R-1A).

ECONOMIC CENSUSES

Title 13 of the United States Code (Sections 131, 191, and 224) directs the Census Bureau to take the economic censuses every 5 years, covering years ending in "2" and "7." The 1992 Economic Census consist of the following eight censuses:

Census of Retail Trade

Census of Wholesale Trade

Census of Service Industries

Census of Financial, Insurance, and Real Estate
Industries

Census of Transportation, Communication, and Utilities
Census of Manufactures

Census of Mineral Industries

Census of Construction Industries

Special programs also cover enterprise statistics and minority-owned and women-owned businesses. (The Census of Agriculture and the Census of Governments are conducted separately.)

The economic censuses have been taken together as an integrated program at 5-year intervals since 1967, and before that for 1963, 1958, and 1954. Prior to that time, the individual censuses were taken separately at varying intervals.

The economic censuses trace their beginnings to the 1810 decennial census, when questions on manufacturing were included with those for population. Coverage of economic activities was expanded for 1840 and subsequent censuses to include mining and some commercial activities. In 1902, Congress established a permanent Bureau of the Census and directed that a census of manufactures be taken every 5 years. The 1905 manufactures census was the first time a census was taken apart from the regular decennial population census.

The first census of business was taken in 1930. Initially it covered retail and wholesale trade and construction industries, but it was broadened in 1933 to include some of the service trades.

The 1954 economic censuses were the first to be fully integrated providing comparable census data across economic sectors, using consistent time periods, concepts, definitions, classifications, and reporting units. These were the first censuses to be taken by mail, using lists of firms provided by the administrative records of other federal agencies. Since 1963, administrative records have also been used to provide basic statistics for very small firms, reducing or eliminating the need to send them census questionnaires. The Enterprise Statistics Program, which

was made possible with the implementation of the integrated census program in 1954.

The range of industries covered in the economic censuses has continued to expand. The census of construction industries began on a regular basis in 1967, and the scope of service industries was broadened in 1967, 1977, and 1987. The census of transportation began in 1963. The survey of minority-owned business enterprises was first conducted as a special project in 1969 and was incorporated into the economic censuses in 1972 along with the survey of women-owned businesses.

The 1992 Economic Census covers more of the economy than any previous census. New for 1992 are data on communication, utilities, financial, insurance, and real estate, as well as, coverage of more transportation industries. The economic, agriculture, and governments censuses now collectively cover nearly 98 percent of all economic activity.

Among other changes, new 1992 definitions affect the boundaries of about a third of all metropolitan areas. Also, the Survey of Women-Owned Businesses has now been expanded to include all corporations.

The core data from the economic censuses and surveys are collected and published in terms of "establishments"; for example, the sales of sporting goods stores in Cleveland, the production of fertilizer plants in Florida, or the employment in electronic repair shops. An establishment, as defined for census and survey purposes, is a business or industrial unit at a single geographic location that produces or distributes goods or performs services, for example, a single store or factory.

Because different establishments within the same company can be located in different geographic areas or be engaged in different kinds of business, the Census Bureau obtains separate reports for each establishment. This yields more precise information than if the company were simply to file a single report.

When more than one economic activity is conducted at a single location, each activity under separate ownership is regarded as a separate establishment. Thus, a leased department within a department store is classified as a separate establishment.

Establishments functioning primarily to manage service or support the activities of their companies' operating establishments (for example, separate administrative offices or warehouses) are identified as auxiliaries, and statistics are published in a separate report.

Establishments responding to the establishment survey are classified into industries on the basis of their principal product or activity (determined by annual sales volume) in accordance with the 1987 Standard Industrial Classification (SIC) Manual. This is the system of industrial classification developed by experts on classification in government and private industry under the guidance of the Office of Information and Regulatory Affairs, Office of Management and Budget. This classification system is used by

side the government. The SIC is a classification structure for the entire national economy.

The structure provides data on a division and industry code basis, according to the level of industrial detail. For example, manufacturing is a major industrial division, food and kindred products (code 20) is one of its major groups. One of the ways this group is further divided is into meat products (code 201) and meat packing plants (code 2011).

Periodically, the SIC is revised to reflect changes in the industrial composition of the economy. The 1987 edition of this manual represents revisions from the 1972 edition and its 1977 supplement. For more information on these revisions, see Appendix A of the 1987 SIC Manual.

More information about the scope, coverage, classification system, data items, and publications for each of the economic censuses and related surveys is published in the Guide to the Economic Censuses and Related Statistics. More information on the methodology, procedures, and history of the censuses is published in the History of the 1992 Economic Censuses.

In accordance with federal law governing census reports, no data are published that would disclose the operations of an individual establishment or business. However, the number of establishments in a kind-of-business classification is not considered a disclosure, so this information may be given even though other information is withheld.

Table A-States

Table A consists of 56 tables with 869 items of data for each state, the United States as a whole, and the District of Columbia. These tables are numbered A-1 through A-56.

A number of the statistics in tables A-1 through A-56 are also presented for metropolitan areas in tables B-1 through B-10 and for metropolitan area component counties in tables C-1 through C-3.

Table A-1. Area and Population

Area, total, land, and water, 1990;
Population, 1997, 1995, 1990, and 1980;

Rank and per square mile of land area, 1997 and 1990;

Population change, net change, net migration, and percent change, 1990-1997;

Percent change 1980-1990.

Source: Area-U.S. Bureau of the Census, 1990 Census of Population and Housing, series CPH-2; and unpublished data from the TIGER/Geographic Identification Code Scheme (TIGER/GICS) computer file. Population-U.S. Bureau of the Census, 1990 Census of Population and Housing, Population and Housing Unit Counts, (CPH-2); Current Population Reports, series P25, No. 1127; and ST-97-1 Estimates of the Population of States: Annual Time Series, July 1, 1990, to July 1, 1997, release date, December 31, 1997, Internet site <http://www.census.gov/population/estimates/

lation change-ST-97-3, Estimates of the Population of States: Annual Time Series, July 1, 1990, to July 1, 1997, and Demographic Components of Population Change, Annual Time Series July 1, 1990, to July 1, 1997, release date: December 31, 1997; Intemet site <http://www.census.gov/ population/estimates/state/STCOM97R2.txt> (accessed 4

February 1998).

The Census Bureau provides measurements for both land area and total water area for the 1990 census. Area was calculated from the specific set of boundaries recorded for the entity in the Census Bureau's geographic database.

Land area measurement may disagree with the information displayed on census maps and in the TIGER file because, for area measurement purposes, features identified as "intermittent water" and "glacier" are reported as land area. TIGER is an acronym for the new digital (computer-readable) geographic database that automates the mapping and related geographic activities required to support the Census Bureau's census and survey programs; TIGER stands for Topologically Integrated Geographic Encoding and Referencing system.

The water figure includes inland, coastal, Great Lakes, and territorial water. "Inland water" consists of any lake, reservoir, pond, or similar body of water that is recorded in the Census Bureau's geographic database. It also includes any river, creek, canal, stream, or similar feature that is recorded in that database as a two-dimensional feature (rather than as a single line). The portions of the oceans. and related large embayments (such as the Chesapeake Bay and Puget Sound), the Gulf of Mexico, and the Caribbean Sea that belong to the United States and its possessions are considered to be "coastal" and "territorial" waters; the Great Lakes are treated as a separate water entity. Rivers and bays that empty into these bodies of water are treated as "inland water" from the point beyond which they are narrower than one nautical mile across. Identification of land and inland, coastal, and territorial waters is for statistical purposes and does not necessarily reflect legal definitions thereof.

The accuracy of any area measurement figure is limited by the inaccuracy inherent in (1) the location and shape of the various boundary features in the database, and (2) rounding affecting the last digit in all operations that compute and/or sum the area measurements.

Population data for 1997 and revised population data for 1990 through 1996 were released in late December of 1997 for states. These population data were processed and used in Table A-1 of this publication. Population figures used to calculate rates or describe various population characteristics (e.g., race) in Tables A-2 through A-56 are those released in the previous annual cycle.

Figures on total persons for 1990 and 1980 are based on a complete, or 100-percent count of population as of April 1 for year shown.

Persons per square mile is the average number of inhabitants per square mile of land area. These figures are

number of square miles of land area in the specified geographic area. To determine population per square kilometer, multiply the population per square mile by .3861. Rank numbers are assigned on the basis of population size, with each area placed in descending order, largest to smallest. Where ties occur-two or more areas with identical populations-the same rank is assigned to each of the tied areas. In such cases, the following rank number is omitted so that the lowest rank is usually equal to the number of areas ranked. Population ranks for 1990, used April 1 corrected data and 1996 July 1 data, respectively.

The Census Bureau estimates the number of foreign immigrants who move into a county during the estimate interval. The county estimates are based on the national estimate of foreign migration developed by the Census Bureau. Estimates include emigration from the United States and the immigration of refugees, legal immigrants, undocumented immigrants, net movement from Puerto Rico, and federal and civilian citizen movement from abroad. The national estimate of the number of undocumented immigrants is allocated to states by using the distribution of the foreign-born population who arrived between 1985 and 1990 and were enumerated as residents in the 1990 census. Legal immigrants and refugees are distributed to counties on the basis of county of intended residence as reported to the Immigration and Naturalization Service.

Estimated net domestic migration is based on individual federal income tax returns. The Census Bureau determines the status of the filer by noting the address, used as a proxy for place of residence, on tax returns filed in the prior year and in the estimate year. The filers are categorized in each county into: (1) inmigrants (INS), (2) outmigrants (OUTS), and (3) nonmigrants (NONMOVERS). The Census Bureau derives a net migration rate for each county based on the difference between the inmigration and outmigration of tax filers and his or her dependents. This rate is used to produce the estimate. If this figure is preceded by a minus sign (-), the figure indicates net outmigration; otherwise, the figure represents net inmigration.

For further discussion of the methodology and guidance in the selection of a particular series, see sources.

Table A-2. Population by Residence and Projections

Metropolitan and nonmetropolitan area population; total, 1994 and 1990 and percent change 1990-1994; Projections, series A and B, 2000, 2005, and 2010.

Source: Metropolitan areas-U.S. Bureau of the Census, 1990 Census of Population and Housing, Supplementary Reports, Metropolitan Areas as Defined by the Office of Management and Budget, June 30, 1993, (1990-CPH-S-11); 1990 Census of Population and Housing, Population and Housing Unit Counts (CPH-2-1); Current Population Reports, P25-1127 and Population Paper Listings PPL-27.

Listings, Population Projections for States by Age, Sex, Race, and Hispanic Origin: 1995 to 2025, PPL-47, October 1996.

Data for metropolitan areas refer to 253 metropolitan statistical areas and 18 consolidated metropolitan statistical areas defined by the U.S. Office of Management and Budget as of June 30, 1995; nonmetropolitan is the area outside metropolitan areas.

The population projections are the results of using the cohort-component method. This method requires separate assumptions for each of the components of population change: births, deaths, internal migration, and international migration. Series A is a modified linear trend of the patterns of state-to-state migration observed from 1975-76 through 1993-94. Series B is the economic model, which uses the Bureau of Economic Analysis employment projections.

Table A-3. Population by Age Group and Sex

Population, by age, 1996, and percent of population under 18 and 65 years and over, 1996, 1990, and 1980; Males per 100 females, 1996.

Source: Age-U.S. Bureau of the Census, Press release CB97-64; Population for computation-U.S. Bureau of the Census, 1990 Census of Population and Housing, Population and Housing Unit Counts, (CPH-2); Sex-U.S. Bureau of the Census, Internet site <http://www.census.gov/population/ estimates/state/96agesex.txt> (accessed 21 July 1997).

For 1996, age represents the number of completed years from birth to July 1; for 1990, data show completed years from birth to April 1.

=

The method used to produce age and sex population estimates is an updated version of a component procedure that has been modified to estimate state populations by single year of age and sex. The component procedures apply only to the population under 65 years of age. For each individual age, the estimating procedure follows the standard demographic formula of P1 Po + B-D + M, where P1 is the population on the estimate date; po is the population on the census date; B and D are the births and deaths occurring during the estimate period (between the census and the estimate date); and M is the net migration (including net immigration from abroad) occurring during the estimate period. The population estimates for ages 65 and over are derived using changes in medicare enrollment.

Table A-4. Series A Population Projections by Age Group

Population projections by age, 2000 and 2005 and percent of population in 2000-under 18 and 65 years and over.

Listings, Population Projections for States by Age, Sex, Race, and Hispanic Origin: 1995 to 2025, PPL-47, October 1996.

The projections for age were prepared using a cohort component method whereby each component of population change-births, deaths, internal migration, and international migration-is projected separately for each birth cohort by sex and race. Series A is the preferred series model and uses state-to-state migration observed from 1975-76 through 1993-94. The source also contains a description of the process by which the cohort-component method is then applied to produce the projections.

Table A-5. Population by Race

White, Black, Asian and Pacific Islander, and American Indian, Eskimo, and Aleut, 1990, 1996, and 2000 projections;

Percent of total, White, Black, Asian and Pacific Islander, and American Indian, Eskimo, and Aleut, 1996.

Source: Race-U.S. Bureau of the Census, Estimates of the Population of States by Race and Hispanic Origin: July 1, 1996, Internet site <http://www.census.gov/population/ estimates/state/srh/srhus96.txt> (accessed 04 March 1998). Projection-U.S. Bureau of the Census, Population Paper Listings, Population Projections for States by Age, Sex, Race, and Hispanic Origin: 1995 to 2025, PPL-47, October 1996.

The White population includes persons who indicated their race as "White" or reported entries such as Canadian, German, Italian, Lebanese, near Eastern, Arab, or Polish.

The Black population includes persons who indicated their race as "Black or Negro" or indicated their race as African American, Afro-American, Black Puerto Rican, Jamaican, Nigerian, West Indian, or Haitian.

The American Indian, Eskimo, and Aleut population includes persons who indicated their race as Indian (American) or who did not indicate a specific race category but reported the name of an Indian tribe, as well as persons who indicated their race as Eskimo or Aleut.

The Asian and Pacific Islander population includes persons who indicated their race as Chinese, Filipino, Japanese, Asian Indian, Korean, Vietnamese, Hawaiian, Samoan, and Guamanian, as well as persons who provided write-in entries of such Asian and Pacific Islander groups as Cambodian, Laotian, Pakistani, and Fiji Islander. Also, persons who did not classify themselves in one of the specific race categories but wrote in an entry indicating one of the specific categories were classified accordingly.

The projections for race were prepared using a cohort component method whereby each component of population change births, deaths, internal migration, and international migration- is projected separately for each birth cohort by sex and race. Series A is the preferred series

1975-76 through 1993-94. The source also contains a description of the process by which the cohort-component method is then applied to produce the projections.

For a detailed description of methodology and data accuracy, see source.

Table A-6. Hispanic Origin, Immigrants Admitted, and Households

Hispanic origin and non-Hispanic White, 1990, 1996, and 2000 projections;

Percent of total, Hispanic origin, and non-Hispanic White, 1996;

Immigrants admitted, 1995, 1994, and 1990; Households, number, percent change, and persons per household, 1996 and 1990

Source: Hispanic origin-U.S. Bureau of the Census, Estimates of the Population of the States by Race and Hispanic Origin: July 1, 1996; Internet site <http://www. census.gov/population/estimates/state/srh/srhus96.txt>(accessed 04 March 1998); Projections-U.S. Bureau of the Census, Population Paper Listings, Population Projections for States by Age, Sex, Race, and Hispanic Origin: 1995 to 2025, PPL-47, October 1996; Immigrants-U.S. Immigration and Naturalization Service, Statistical Yearbook, annual; Households-U.S. Bureau of the Census, Estimates of Housing Units and Households of States: 1990 and 1996, Population Paper Listings PPL-73.

Persons of Hispanic origin may be of any race.

Immigrants are identified as aliens (new arrivals and persons adjusting their status) who are admitted for legal permanent residence in the United States. Immigration statistics are prepared from entry visas and change of immigration status forms. Data are shown by state of intended residence.

Households consist of all the persons who occupy a "housing unit;" that is, a house, an apartment or other group of rooms, or single room that constitutes "separate living quarters." A household includes the related family members and all the unrelated persons, if any, such as lodgers, foster children, wards, or employees who share the housing unit. A person living alone or a group of unrelated persons sharing the same housing unit is also counted as a household. The method used to prepare the estimates of households by state is based on national trends and state trends in the adult population (18 years and over) per household and on estimates of the adult population for states.

Persons per household represents the number of persons in households divided by the number of households (or householders).

For a detailed description of methodology and data accuracy, see source.