Year	% of tax revenue
1972	30.16336056009335
1973	28.441295546558703
1974	28.205128205128204
1975	24.759229534510432
1976	25.508905852417303
1977	26.349496797804207
1978	26.29750715161422
1979	25.364077669902912
1980	21.401000714796282
1981	28.636818766986128
2003	9.334569385301847
2004	8.335931727027708
2005	8.156479803501625
2006	7.484992794632717
2007	7.5225058215985285
2008	7.0284815210303995
2009	5.290387204287439
2010	5.8025632176187045
2011	5.300759892652648
2012	5.502932363941522
2013	4.67411800004762
2014	4.3356182017805045
2015	4.434362432746328
2020	3.9740159711054552