VitalStats, "tables, data files, and reports that allow users to access and examine vital statistics and population data interactively." From the Centers for Disease Control and Prevention's National Center for Health Statistics.
Vital Statistics Data Available Online, downloadable public use data files from the Centers for Disease Control and Prevention's Division of Vital Statistics.
CDC Wonder, including birth and death data from the Centers for Disease Control and Prevention.
According to the Statistical Abstract of the United States, the registration of vital events in the U.S. is done at the state and local levels. "Vital statistics are collected and disseminated for the nation [...] by the National Center for Health Statistics (NCHS). [...] Reports are also issued by various state bureaus participating in the National Vital Statistics System." Begin to look for these reports via State Health Departments.
Major sources of statistics on vital events (births, marriages, divorces, deaths, and fetal deaths) are listed to the left.
The Statistical Abstract of the United States (section 2) is another great place to start looking. Even if the data that you want are not there, look at the footnotes for relevant tables and the introduction to section 2 for pointers to more comprehensive sources. Previous editions, 1878-, are also available.
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