Data for this article, as in previous reports, are drawn principally from the Monthly Vital Statistics Report, published by the National Center for Health Statistics. The international data come from the Demographic Yearbook and the quarterly Population and Vital Statistics, both published by the Statistical Office of the United Nations, and the World Health Statistics Report, published by the WHO. All the USA data for 1975 are estimates based upon a 10% sample of material received in state offices between 2 dates, 1 mo. apart, regardless of when the event occurred. For the country as a whole the estimate is very close to the subsequent final figures. There are, however, considerable variations in a few of the states; state information should be interpreted cautiously.