Year	% of tax revenue
1972	7.1558300036324
1973	9.615994922246905
1974	15.382792130836693
1975	26.520387007601936
1976	12.955542835336766
1977	15.736393670665972
1978	7.35020468924451
1979	8.935047807451369
1980	8.509111780743291
1981	11.968954248366014
1982	1.56155245603396
1983	0.8207232623749678
1984	1.8640665328362491
1985	2.6286390221462836
1986	5.224327018943171
1987	3.0803429660209587
1988	4.651646807846402
1989	2.4513351872309626
1990	0.0837426523874708
1991	0.033053973940673484
1992	0.013951158263207626
1993	0.006579308076100663
1994	0.00513771649052862
1995	0.017224094299708073
1996	0.018080879059465545
1997	0.006252735571812669
1998	0.004666880794138397
1999	0.00519641200123724
2000	0.006897560771690738
2001	0.004160140417731264
2002	0.0036215992740900667
2003	0.2822633046071399
2004	1.4554846418208773
2005	0.009140771205003251
2006	0.039077628940735194
2007	0.03800381107476591
2008	0.054460163452059854
2009	0.060023403757498234
2010	0.06043579228057071
2011	0.0666664135540303
2012	0.08497065997670633
2013	0.00955279231293567
2014	0.003080213749288172
2015	0.002025034202436628
2018	0.00989206594501853