1 School of Public Health, University of Michigan, Ann Arbor, Michigan
Births in 1971 were lower than in 1970 (Table I); the birth rate turned down again; deaths were about the same; and the natural increase in population, 1,638,000 or 0.8%, was the lowest in several years. Infant mortality continued to drop slowly, marriages were down slightly, and divorces were up slightly.
Data for this article, as in previous reports, are drawn principally from two sources: the Monthly Vital Statistics Report, published by the National Center for Health Statistics, and the Demographic Yearbook and the monthly quarterly, Population and Vital Statistics, published by the Statistical Office of the United Nations. The limitations on the data used are explained in these reports and do not differ from previous years.