“The United States Social Security Administration (SSA) is an independent agency of the United States federal government that administers Social Security, a social insurance program consisting of retirement, disability, and survivors’ benefits. To qualify for these benefits, most American workers pay Social Security taxes on their earnings; future benefits are based on the employees’ contributions.”
From Wikipedia: http://en.wikipedia.org/wiki/Social_Security_Administration
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Social Security Administration Home
http://www.ssa.gov/
Social Security statistical tables
http://www.ssa.gov/OACT/STATS/index.html
Social Security annual statistical supplement
http://www.ssa.gov/policy/docs/statcomps/supplement/
Medicare Amendment to Social Security Act TITLE XVIII
http://www.ssa.gov/OP_Home/ssact/title18/1800.htm
Health Reform Trends, Research and Analysis 