INTRODUCTION

OVERVIEW

This volume is the 12th in the County and City Data Book series. It presents a variety of information on States, counties, cities, and places in the United States. These statistics represent useful summary measures that are generally available in comparable form for the geographic areas covered. Among the latest statistics to be found in this book are many of the results of 1990 Census of Population and Housing, particularly sample data on such subjects as labor force, housing, income, and journey to work. Also included are 1992 population estimates for counties and cities and climate data for cities featuring new averages for the period 1961 to 1990. Subjects covered include the following:

ARRANGEMENT OF DATA TABLES

The data in this book are organized in four main data tables. Table A presents 220 data items for the United States as a whole, each census geographic region and division, and the 50 States and the District of Columbia on pages 2 through 15. Table B presents for each county and equivalent area the same 220 data items shown in table A on pages 18 through 647.

Table C presents 194 data items for cities (incorporated places with 25,000 or more inhabitants in 1990) on pages 650 through 853. Table C differs somewhat in content from tables A and B; as examples, climate data, shown for cities, are not available for counties and physician data, shown for counties, are not available for cities.

Table D presents 1990 population and two 1990 census income items for places with 2,500 or more inhabitants in 1990 on pages 856 through 928. This table includes both incorporated places and census designated places for all States and minor civil divisions (MCD's) for the following 12 States: Connecticut, Maine, Massachusetts, Michigan, Minnesota, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Vermont, and Wisconsin.

To assist in interpreting the statistics presented, text describing the data items and geographic concepts is included in appendixes A and B, and maps for each State showing counties, metropolitan areas, and cities of 25,000 or more are provided in appendix C. Appendix D, Table Outlines, has been included to assist in locating data items on tables A through D.

• "S" means data suppressed; does not meet publication standards.

• "X" means not applicable.

• "Z" represents a number or percent that rounds to less than half the unit of measure shown.

The following terms are also used throughout this publication:

• An average is a number or value that is used to represent the "typical value" of a group of numbers. It is a measure of central tendency for a group of numbers.

The mean is an average derived by summing the individual item values of a particular group and dividing the total by the number of items, e.g., average travel time to work. It is often referred to simply as the "mean" or "average."

The median of a group is the middle number or value when each item in the group is arranged according to size, e.g., median household income. It generally has the same number of items above it and below it.

• A rate is a quantity or amount of an item measured in relation to a number of units of another item, e.g., the number of births per 1,000 resident population. The birth rate is obtained by dividing the number of births for a given year by the resident population as of a specified date and multiplying the result by 1,000.

Per capita is a rate per individual, e.g., per capita taxes.

DATA RELIABILITY AND RESPONSIBILITY

All data from censuses, surveys, or administrative records are subject to error arising from a number of factors: sampling variability (for statistics based on samples), reporting errors in the data for individual units, incomplete coverage, nonresponse, imputations, and processing error.

For some items, details may not add to the totals shown; for example, a State total may differ from the sum of its component counties, or the United States total may differ from the sum of the 50 States and the District of Columbia. Rounding of the data may be the reason for these occurrences, or the total may include values that could not be allocated to the lower geographic levels shown. Other examples are generally footnoted in the tables or explained in the text.

The Bureau of the Census cannot accept the responsibility for the accuracy or limitations of the data presented in this publication other than for those it collects. The responsibility for selection of the material and for proper presentation, however, rests with the Bureau.

CONTENTS OF THE APPENDIXES

Appendix A contains source references and definitions for the subject-matter items presented in this report.

X

Appendix B provides definitions of the types of geographic areas and related codes covered in this volume. Also lists metropolitan areas with codes and county definitions to assist users in aggregating county data to metropolitan areas.

Appendix C contains State maps showing counties and equivalent areas, places of 25,000 or more inhabitants, metropolitan areas (MA's) defined as of June 30, 1993, and MA central cities of fewer than 25,000 inhabitants.

Appendix D presents outlines of tables A through D with specific page references to geographic area groupings. This format is used instead of a traditional index because of the number of page references involved for each topic; as examples, vital statistics would need 63 individual page references, and money income would need 182.

RELATED PRODUCTS

Diskettes and CD-ROM's. For further analysis, these data can be obtained in electronic format on 3.5- or 5.25-inch high density diskettes formatted for IBM or compatible personal computers or on a CD-ROM. The diskettes contain data in ASCII, comma-delimited files; included with the diskettes is UTILITY2 software. The CD-ROM version contains data in dBase format and features "GO" software. Another CD-ROM, USA Counties 1994, presents data for over 2,500 variables for all counties and equivalent areas, the 50 States and the District of Columbia, and the United States. This CD-ROM also features dBaseformat data files and "GO" software.

Publications. The County and City Data Book is a supplement to the Statistical Abstract of the United States, which presents an even broader range of data. Though the Abstract presents most data only at the national level, it does feature significant detail for States. Since the Abstract is updated annually, future editions will provide a number of State figures that update those presented here. Another supplement to the Abstract is the State and Metropolitan Area Data Book, most recently issued for 1991, with a number of these same data items presented for States, metropolitan areas, and central cities of metropolitan areas.

For more information on these products, see the inside back cover, call 301-763-1034, or write to the Chief, Statistical Compendia Branch, Data User Services Division, U.S. Bureau of the Census, Washington, DC 20233.

Users of this volume, the Statistical Abstract of the United States, and its other supplements are urged to make their data needs known for consideration in planning future editions. Suggestions and comments for improving coverage and presentation of data should be sent to the Director, U.S. Bureau of the Census, Washington, DC 20233.