This section presents vital statistics data on births, deaths, abortions, fetal deaths, fertility, life expectancy, marriages, and divorces. Vital statistics are compiled for the country as a whole by the National Center for Health Statistics (NCHS) and published in its annual report, Vital Statistics of the United States, in certain reports of the Vital and Health Statistics series, and in the National Vital Statistics Reports (formerly Monthly Vital Statistics Report). Reports in this field are also issued by the various state bureaus of vital statistics. Data on fertility, on age of persons at first marriage, and on marital status and marital history are compiled by the U.S. Census Bureau from its Current Population Survey (CPS; see text, Section 1) and published in Current Population Reports, P20 Series. Data on abortions are published by the Alan Guttmacher Institute, New York, NY, in selected issues of Family Planning Perspectives.

Registration of vital events-The registration of births, deaths, fetal deaths, and other vital events in the United States is primarily a state and local function. The civil laws of every state provide for a continuous and permanent birth- and death-registration system. Many states also provide for marriage- and divorceregistration systems. Vital events occurring to U.S. residents outside the United States are not included in the data.

Births and deaths-The live-birth, death, and fetal-death statistics prepared by NCHS are based on vital records filed in the registration offices of all states, of New York City, and of the District of Columbia. The annual collection of death statistics on a national basis began in 1900 with a national death-registration area of 10 states and the District of Columbia; a similar annual collection of birth statistics for a national birth registration area began in 1915, also with 10 reporting states and the District of Columbia. Since 1933, the birth- and death-registration areas have comprised the entire United States, including Alaska (beginning 1959) and Hawaii (beginning 1960). National statistics on fetal deaths were first compiled for 1918 and annually since 1922.

Prior to 1951, birth statistics came from a complete count of records received in the Public Health Service (now received in NCHS). From 1951 through 1971, they were based on a 50-percent sample of all registered births (except for a complete count in 1955 and a 20- to 50-percent sample in 1967). Beginning in 1972, they have been based on a complete count for states participating in the Vital Statistics Cooperative Program (VSCP) (for details, see the technical appendix in Vital Statistics of the United States) and on a 50-percent sample of all other areas. Beginning 1986, all reporting areas participated in the VSCP. Mortality data have been based on a complete count of records for each area (except for a 50-percent sample in 1972). Beginning in 1970, births to and deaths of nonresident aliens of the United States and U.S. citizens outside the United States have been excluded from the data. Fetal deaths and deaths among Armed Forces abroad are excluded. Data based on samples are subject to sampling error; for details, see annual issues of Vital Statistics of the United States.

Mortality statistics by cause of death are compiled in accordance with World Health Organization regulations according to the International Classification of Diseases (ICD). The ICD is revised approximately every 10 years. The ninth revision of the ICD was employed beginning in 1979. Deaths for prior years were classified according to the revision of the ICD in use at the time. Each revision of the ICD  introduces a number of discontinuities in mortality statistics; for a discussion of those between the eighth and ninth revisions of the ICD, see Monthly Vital Statistics Report (renamed, National Vital Statistics Report), Vol. 28, No. 11, supplement.

Some of the tables present age-adjusted death rates in addition to crude death rates. Age-adjusted death rates shown in this section were prepared using the direct method, in which age-specific death rates for a population of interest are applied to a standard population distributed by age. Age adjustment eliminates the differences in observed rates between points in time or among compared population groups that result from age differences in population composition.

Fertility and life expectancy-The total fertility rate, defined as the number of births that 1,000 women would have in their lifetime if, at each year of age, they experienced the birth rates occurring in the specified year, is compiled and published by NCHS. Other data relating to social and medical factors which affect fertility rates, such as contraceptive use and birth expectations, are collected and made available by both NCHS and the Census Bureau. NCHS figures are based on information in birth and fetal death certificates and on the periodic National Surveys of Family Growth; Census Bureau data are based on decennial censuses and the CPS.

Data on life expectancy, the average remaining lifetime in years for persons who attain a given age, are computed and published by NCHS. For details, see the technical appendix in Vital Statistics of the United States.

Marriage and divorce-The compilation of nationwide statistics on marriages and divorces in the United States began in 1887-88 when the National Office of Vital Statistics prepared estimates for the years 1867-86. Although periodic updates took place after 1888, marriage and divorce statistics were not collected and published annually until 1944 by that office. In 1957 and 1958, respectively, the same office established marriage- and divorce registration areas. Beginning in 1957, the marriage-registration area comprised 30 states, plus Alaska, Hawaii, Puerto Rico, and the Virgin Islands; it currently includes 42 states and the District of Columbia. The divorce-registration area, starting in 1958 with 14 states, Alaska, Hawaii, and the Virgin Islands, it currently includes a total of 31 states and the Virgin Islands. Procedures for estimating the number of marriages and divorces in the registration states are discussed in Vital Statistics of the United States, Vol. III-Marriage and Divorce. Total counts of events for registration and non-registration states are gathered by collecting already summarized data on marriages and divorces reported by state offices of vital statistics and by county offices of registration.

Vital statistics rates-Except as noted, vital statistics rates computed by NCHS are based on decennial census population figures as of April 1 for 1940, 1950, 1960, 1970, 1980, and 1990; and on midyear population figures for other years, as estimated by the Census Bureau (see text, Section 1).

Race-Data by race for births, deaths, marriages, and divorces from NCHS are based on information contained in the certificates of registration. The Census Bureau’s Current Population Survey obtains information on race by asking respondents to classify their race as (1) White, (2) Black, (3) American Indian, Eskimo, or Aleut, or (4) Asian or Pacific Islander.

Beginning with the 1989 data year, NCHS is tabulating its birth data primarily by race of the mother. In 1988 and prior years, births were tabulated by race of the child, which was determined from the race of the parents as entered on the birth certificate.

Trend data by race shown in this section are by race of mother beginning with the 1980 data. Hispanic origin of the mother is reported and tabulated independently of race. Thus persons of Hispanic origin maybe of any race. In 1994, 91 percent of women of Hispanic origin were reported  as White.