Social Security: Major Decisions in the House and Senate Since 1935 [Updated March 28, 2019] [open pdf - 2MB]
From the Document: "The Social Security Act of 1935 established a federal old-age pension financed with employee-employer payroll taxes. Since then, Congress has amended the Social Security program for multiple purposes, including to expand coverage, change the minimum age for retirement benefits, provide an automatic cost-of-living adjustment to benefits, and address concerns about solvency of the Social Security Trust Funds. This report traces the major decisions affecting the Social Security program, from the earliest enacting legislation through the most recent congressional session. It provides a summary of the provisions and voting records for each bill, focusing on amendments to Old-Age, Survivors and Disability Insurance (OASDI). (OASDI is the formal name for Social Security.)"
CRS Report for Congress, RL30920
Congressional Research Service: https://crsreports.congress.gov/