U.S. Cohort and Period Fertility Tables, 1917-1980

Description of data

These fertility tables, produced by the National Institute of Child Health and Development, National Institutes of Health, were compiled by Robert L. Heuser. They are tabulated by single year of age and birth cohort, by parity and race. There are three series of data:

  1. Central birth rates by cohort and age (Cohorts 1868 through 1966). 
  2. Central birth rates by period and age (Years 1917 through 1980).
  3. Cumulative birth rates by cohort to exact age x. (Cohorts 1867 through 1966). 

The ages tabulated are 14 to 49. The numerators were taken from birth registration statistics. The denominators were taken from the U.S. censuses. In the earlier years, births within the birth registration areas were used to estimate births for the entire U.S. Adjustments were made for undercount and age misreporting. Within a cohort, the age-specific rates were smoothed by using a three-year moving average, where it was assumed that the rates below age 14 and above age 49 were 0. 

The earliest year for which birth registration data are available is 1917. The cohort tables (Series 1 and 3) thus begin with women born in 1868, who were 49 in 1917, and end with women born in 1966, who were 14 in 1980, although a complete age schedule is available only for women born between 1903 and 1931. In the cohort tables, rates for ages attained before 1917 or after 1980 are set to 0.

Data Availability

You can click here to download the following files:

  • readme - ascii version of this file
  • cohort.dat - Series 1, central cohort birth rates
  • period.dat - Series 2, central period birth rates
  • cumcoh.dat - Series 3, cumulative cohort birth rates

Format of data

The records in the files have the following format:

year 1-4 Series 1 and 3: year of woman's birth Series 2: year of birth of child series 5 Series number (1,2,or 3) race 6 0=all; 1=white; 2=black and other parity 7 0=all births; 1=first births; 8=8th and higher order births record 8 (1, 2, or 3. See "rates") rate 9-80 12 six-digit rates with four implied decimal points. Record 1: rates at ages 14-25 Record 2: rates at ages 26-37 Record 3: rates at ages 38-49

Note: The rates for the cumulative tables (Series 3) are for exact age x. The rate for age 14 represents cumulative fertility to exact age 14 and has been set to 0 for all cohorts. The rates for age 49 do not include births at age 49. 

Key Reference

Heuser, Robert L. Fertility tables for birth cohorts by color.  U.S. Department of Health, Education, and Welfare. DHEW Publication No. (HRA)76-1152

This book published the fertility tables through 1973. It contains valuable information about the method of calculating the rates and adjustments for undercount and age misreporting. It also contains estimated completed fertility for the cohorts born before 1903, using census data to supply the completed fertility for ages attained before 1917.