Table 2.1 Table 2.1 Income tax rates and labor supply Marginal Federal Tax Rate Average Weekly (percent) Hours 1955 20.00 % 39.6 1960 20.00 38.6 1965 17.00 38. 1970 19.48 37.1 1975 22.00 36.1 35.3 1985 29.05 34.9 1990 34.5 34.5 2001 22.65 4.5 MTax Policy Center, Historical Combined Income and Employee Tax Rates for a Family of Four, " URI http://www.taxpolicycenter.org/taxfacts/overview/combined_family.cfmJanuary15.2003 TEconomic Report of the President, 2002.(Washington DC: US Government Printing Office. 2002), p. 376Table 2.1