Source: 1900-1970, U.S. Public Health Service,
Vital Statistics of the United States, annual, Vol.
I and Vol II; 1971-2001, U.S. National Center for Health
Statistics, Vital Statistics of the United States,
annual; National Vital Statistics Report (NVSR)
(formerly Monthly Vital Statistics Report);
and unpublished data. From Statistical Abstract of
the United States: 2003.