Sources: Tempalski, Jerry. "Revenue Effects of Major Tax Bills." OTA Working Paper 81 , July 2003 for years 1940 - 1980. U. S. Department of the Treasury, Office of Tax Analysis (November 1, 1988); and Office of Management and Budget, Budget of the United States Government, various fiscal years. Summary of 1990 OBRA abstracted from U. S. House of Representatives Budget Committee, Summary of Reconciliation Conference Report, October 1990. Joint Committee on Taxation budget estimates and technical explanations used for 1996 and later. Library of Congress public law summaries used for 2001 and later.