The Supplement is a major resource for data on programs administered by the Social Security Administration—the Old-Age, Survivors, and Disability Insurance program, known collectively as Social Security, and the Supplemental Security Income program. The Supplement also includes program summaries and legislative histories that help users of the data understand these programs. Please note that additional disability tables and statistics can be found in the SSI Annual Statistical Report and the Annual Statistical Report on the Social Security Disability Insurance Program.

The Supplement has been published annually since 1940. Decisions affecting the future of Social Security are facilitated by the availability of relevant data over a long period. The data provide a base for research, policy analysis, and proposals for changing the programs. In addition to meeting the Social Security Administration's information needs, the Supplement strengthens the agency's ability to respond to requests for program data from congressional committees, government agencies at all levels, and the research community.

The Supplement is prepared by Social Security Administration staff from various components throughout the agency. I would like to express my thanks to them for their contributions.

Katherine N. Bent
Acting Associate Commissioner for Research, Evaluation, and Statistics
February 2021