SSI Annual Statistical Report, 2010 – Social Security Administration, Office of Retirement and Disability Policy, Office of Research, Evaluation, and Statistics, August 2011. Size and Scope of the Supplemental Security Income Program and Profile of Recipients as follows:

• “About 7.9 million people received federally administered payments in December 2010.
• The average monthly payment in December 2010 was $501.
• Total payments for the year were more than $48 billion, including almost $4 billion in federally administered state supplementation.
• The majority were female (55 percent).
• Sixteen percent were under age 18, 58 percent were aged 18 to 64, and 26 percent were aged 65 or older.
• Most (85 percent) were eligible on the basis of a disability.
• Six out of 10 recipients under age 65 were diagnosed with a mental disorder.
• More than half (57 percent) had no income other than their SSI payment.
• Thirty-four percent of SSI recipients also received Social Security benefits.
• Of the people receiving SSI benefits, about 2 percent were residing in a Title XIX institution where Medicaid was paying more than half of the cost.
• Despite their disabilities, about 319,000 recipients (4.7 percent) were working in December 2010.