Year	% of tax revenue
1973	0.7086675492562884
1974	0.30251141552511446
1975	0.7407015501825303
1976	1.477682811016146
1977	0.2596789423984893
1978	0.1795547043332532
1979	0.1453094121749911
1980	0.09015481271746306
1981	0.050531151306345126
1982	0.05890700725627219
1983	0.04923613651070538
1984	0.045278337726779305
1985	0.045426412051627084
1986	0.046290610563706217
1987	0.041434987168520086
1988	0.056358708347391914
1989	0.018024985907738343
1990	0.014319655626894053
1991	0.015382810361235321
1992	0.02097128380414263
1993	0.017260096020639444
1994	0.010341842871435171