"This index is a master index file of deaths reported to the Social Security Administration. It has been kept since 1962, when operations were computerized. The index includes about 50 percent of deceased persons from 1962 to 1971 and about 85 percent of the deceased persons from 1972 to 2005. It also includes a few deaths from 1937 to 1961. As of 2005, the index contained 76 million death records." See FamilySearch Wiki: United States Social Security Death Index to learn more.