Year	% of tax revenue
1988	20.01817871414608
1989	19.722305576592163
1990	17.024299361248225
1991	17.084467031155416
1992	15.178677116562547
1993	15.454381385222199
1994	12.889165216224821
1995	13.527746582373274
1996	12.564186399329447
1997	12.483357947794858
1998	11.681049955288659
1999	10.727195104419078
2000	10.598667520897589
2001	10.7096526324766
2002	10.792173571029885
2003	10.014749650427952
2004	9.826342506966387
2005	10.138352252313728
2006	9.562029096400332
2007	10.065829183465485
2008	9.906218648575752
2009	8.406639045465885
2010	8.547057241591402
2011	8.471830270967466
2012	8.821475174566434
2013	8.605554241474824
2014	8.306444961715792
2015	8.276679668029958
2016	8.866554392875567
2017	8.795661587214731
2018	8.992824192790176
2019	8.93371830640159
2020	8.98768917540926