The numbers were initially assigned at local post offices, until the Social Security field offices were established beginning in 1936. Since 1972 the cards have been issued out of Baltimore, not the field offices. Beginning in 1967, the Department of Defense began using Social Security numbers in place of military service numbers. Since 1972 Social Security numbers have been assigned to legally admitted aliens upon entry to the U.S. Since 1989, parents may automatically obtain a Social Security number for a newborn infant when the birth is registered with the state. Since 1962 a database has been maintained of all deaths reported to the Social Security Administration.
Some funeral homes report all deaths, but that is by no means a universal activity.
Government employees, spouses with no earned income and self-employed persons, who are not eligible for Social Security benefits, are generally not included. For those who are in the database, information may be incomplete. Only the FamilySearch edition seems to include foreign deaths. Now for the GOOD news. As of August 1999, there were nearly 62 million individuals in the database.