to the county, or counties, containing such a city, or cities, contiguous counties are included in a standard metropolitan area if according to certain criteria they are essentially metropolitan in charecter and socially and economically integrated with the central city. In New England, standard metropolitan areas have been defined on a town rather then county besis. Central cities.--The largest city in a standard metropolitan area is the principel central city. In 1950, eny other city of 25,000 inhabitants or more within a standard metropolitan area was also designated as a central city. However, the maximum number of central cities permitted in any standard metropolitan area was three. In the cese of the New YorkNortheastern New Jersey Standard Metropolitan Area, Jersey City and Newark were also considered central cities. The data for central cities for 1956 shown in this report relete to the cities es constituted in 1950, that is, annexations since April 1950 have not been taken into account. Percentages.--Percentages are shown as calculeted; therefore, they do not always add to exactly 100.0 percent. The totals, however, are always shown as 100.0 percent. SOURCE AND RELIABILITY OF THE ESTIMATES Source of data.--The estimates presented in this report are based on date obtained in connection with the monthly population sample survey of the Bureau of the Census. This sample is spread over 230 sample areas comprising 453 counties and independent cities. A total of 24,000 to 26,000 dwelling units and other living quarters are designated for the sample at any time, and completed interviews are obtained each month from about 20,000 to 22,000 households. Of the remainder, about 500 to 1,000 are households for which information should be obtained but is not, and the rest are vacant dwellings or those otherwise not to be enumerated for the survey. Reliability of the estimates.--Since the estimates for March 1956, presented in this report, are besed on a sample, they are subject to sampling variability. The stenderd error is a measure of sampling variability. The chances are about 68 out of 100 that the difference due to sampling variability between an estimate and the figure that would have been obtained from a complete count is less than the standard error. The chances are about 95 out of 100 that the difference is less than twice the standard error and 99 out of 100 that it is less than 2 times the error. To illustrate, the survey showed 2,617,000 persons 35 to 44 years of age living on rural farms. This figure has a standard error of about 90,000. The chances are about 68 out of 100 that a complete count of such persons would show not less than 2,527,000 persons nor more than 2,707,000 persons. These persons constitute 12.2 percent of the total number of persons living on rural farms. The standerd error on the 12.2 percent is about 0.4 percentage points. Caution should be exercised in considering trends or comparisons of these data from one year to the next; comparisons over relatively longer periods will provide more reliable evidence of the extent of change. Estimates of annual change are sensitive to small errors in the estimates of the total number of persons in a category. The joint effect of sampling variability and any biases in response or coverage on the total number of persons in a given category for each year may, therefore, be large in relation to the amount of annual change. Table 1.--CIVILIAN POPULATION BY AGE AND SEX, FOR THE UNITED STATES, URBAN AND RURAL: MARCH 1956 AND APRIL 1950 (Figures for 1950 for age groups 55 to 69 years adjusted for apparent age bias in the nonwhite population; see text for explanation) In comparison with the adult population in other parts of the United States, a larger proportion of the residents of areas contiguous to American cities are married persons, according to estimates obtained from the Current Population Survey conducted by the Bureau of the Census in March 1956. Relatively smaller proportions of the "suburban" population of marriageable age were single, widowed, or divorced. Specifically, about 70 percent of the people 14 years old or over living within standard metropolitan areas but outside their central cities were married and living with their spouses, while only 61 percent of those living in the central cities of these areas were in this category. The national average proportion was intermediate--65 percent. The territory in standard metropolitan areas outside central cities includes most of the suburban development, as well as some less densely settled territory. Within this area outside the central cities, most of the suburban growth since 1950 is in the rural-nonfarm territory and most of the suburban development prior to 1950 is in the urban territory. The newly developed suburban areas have a higher proportion married than the older peripheral areas. Married persons in the rural-nonfarm populatior within standard metropolitan areas comprise 77 percent of the total, whereas in the urban territory outside central cities they comprise only 70 percent. The proportion married is lowest and the proportions widowed and divorced are highest in the central cities. The percent single is highest (24 percent) for the rural-farm population within standard metropolitan areas (figure 1 and table 4). The figures presented in this report relate primarily to the civilian population. This population includes 872,000 members of the Armed Forces in 1956 and 547,000 in 1950 who were living off post or with their families on post, but excludes all other members of the Armed Forces. The figures are For sale by the Bureau of the Census Price 10 cents The data for males are greatly influenced by the size of the Armed Forces, which has expanded appreciably since 1950. Most of the members of the Armed Forces are men under 35 years of age and single. Thus, the decrease in percent single and the increase in percent married among males 14 years old and over from 1950 to 1956 could be very largely a function of the increase in size of the Armed Forces over the same period. However, if the analysis is limited to the population 35 years old and over, the same trends are evident: among men 35 and over, the proportion single declined from 9.6 percent in 1950 to 8.3 percent in 1956; the percent married increased from 81.3 to 82.8; and there was little change in the proportions of males who were widowed and divorced. Little change was manifested in the marital status distribution of females. MALE Unstandardized United States...... 100.0 23.8 70.4 4.1 1.6 Urban...... 100.0 23.2 70.7 4.2 1.9 1 Age distribution of the United States used as standard. Farm women had a slightly higher proportion married and lower proportions widowed and divorced than nonfarm women. Among men, on the other hand, the lowest percent married occurred in the ruralfarm population and the highest percent was in the rural-nonfarm population. There was only about half as large a proportion of divorced males in the rural-farm as in the urban population. Differences among the residence groups in percentages who were widowers were small. Part of the difference in the marital status distributions for the three residence groups is due Armed Forces obtained from the Department of Defense. Census data by single years of age were used for 1890 to 1940. Sample survey data by 5-year age groups, reduced to comparable intervals by interpolation methods, were used for 1947 to 1956. For 1940, the corresponding medians using 5-year age groupings are 24.3 years for men and 21.5 years for women. (For a discussion of the method used in estimating the medians, see the section below on "Definitions and explanations.") Differences from year to year which may be computed from table C for recent years should be used with the full realization that such annual changes are not precise measures. Because of sampling variability of the survey data and the limitations of the estimating technique itself, the errors in the estimates of the median age may be larger than the annual changes since 1950. PERCENT WHO ARE HEADS CONTINUES TO INCREASE There has been a long-time tendency for more of the adults to be heads of households. In 1956, four out of every ten persons 14 years old and over (41 percent) were heads of households, whereas in 1890 only three persons out of every ten in this age range (31 percent) were household heads (table D). The most rapid rise in the proportion of the population who were heads occurred during the decade of the 1940's, reflecting the high marriage rate and the consequent high rate of family formation which prevailed during the period. rapid (2) (2) during (2) (2) (2) (2) (2) (2) (2) |