Year	% of tax revenue
1972	15.555555555555555
1973	19.565217391304348
1974	15.254237288135593
1975	22.78481012658228
1976	17.82178217821782
1977	13.986013986013987
1978	16.39344262295082
1979	13.737373737373737
1980	16.259298618490966
1981	23.227206946454416
1982	21.120497999110714
1983	21.243677476941386
1984	22.35767248963177
1985	22.582990065422827
1986	21.46323529411765
1987	22.710983405436817
1988	14.745308310991955
1989	17.65526866713189
1990	10.689614000375254
1991	11.197781421098902
1992	11.879088150972807
1993	14.354916209402344
1994	13.073309659746274
1995	12.650309581533264
1996	11.592611057447625
1997	10.431125697171858
1998	11.713288224060008
1999	11.971610833733543
2000	11.611387312685558
2001	10.62449289953145
2002	9.085347607806629
2003	8.148821187606506
2004	7.699077820162088
2005	7.460238919912348
2006	5.224298013415065
2007	3.0481154917714135
2008	3.2806117467971565
2009	2.8373680456320436
2010	2.796890489242626
2011	1.827290729382259
2012	1.8149918634644904
2013	1.909830686295402
2014	1.877755265617013
2015	1.9678400910918863
2016	1.7982081537348233
2017	1.5971029276954323
2018	1.3916501116691706
2019	1.2870080235403822
2020	1.2450116828822808
2021	1.0468563399648436