Year % of tax revenue 1972 22.22222222222222 1973 27.27272727272727 1974 25 1975 14.285714285714285 1976 14.634146341463413 1977 9.836065573770492 1978 6.315789473684211 1979 5.41871921182266 1980 4.751131221719457 1981 5.289421157684631 1982 6.525037936267071 1983 5.4363796650014695 1984 4.285982243341253 1985 4.7225439612509215 1986 4.8370724955303075 1987 3.6991620682607804 1988 2.85619437417533 1989 1.7099406249765428 1990 1.5994939737154417 1991 1.8436601982499758 1992 1.9010332579916047 1993 1.2878344409627767 1994 0.7612863500237902 1995 1.110988755521296 1996 1.0566731559593339 1997 1.0233140947752126 1998 0.9690384700322423 1999 1.0051953919132595 2000 0.9682189078858329 2001 0.922443248775581 2002 0.9474147538500584 2003 0.9656535227599384 2004 1.0567953515411421 2005 1.0860314390824788 2006 1.0582578193184013 2007 1.1578718956277587 2008 1.2892006116246966 2009 1.3472272968491767 2010 1.3661652142899705 2011 1.3672582745875348 2012 1.15809525487751 2013 0.9475878221864209 2014 1.080002445684306 2015 1.055010909580704 2016 1.1538488805904692 2017 0.9628828894473562 2018 0.9072680637266086 2019 0.9506231023106055 2020 0.9225606068103119 2021 0.9466064268149671 2022 0.6736950100366058