Year	% gross
1974	26.5465106964111
1975	27.9128303527832
1976	30.2681407928467
1977	30.4765300750732
1978	30.2551307678223
1979	30.9881191253662
1980	31.0771808624268
1981	30.0644302368164
1982	30.408130645752
1983	31.0718193054199
1984	30.8302001953125
1985	30.5657901763916
1986	30.8439292907715
1987	30.3936595916748
1988	31.4397506713867
1989	31.5225791931152
1990	31.6581401824951
1991	32.816349029541
1992	33.0858497619629
1993	34.2798805236816
1994	34.2123107910156
1995	34.5500411987305
1996	35.2109107971191
1997	35.622989654541
1998	35.1414909362793
1999	35.3539581298828
2000	35.4734306335449
2001	36.3060417175293
2002	37.8762397766113
2003	38.1159286499023
2004	39.6958885192871
2005	40.4352684020996
2006	40.5208892822266
2007	41.1438789367676
2008	42.826961517334
2009	43.8107604980469
2010	43.5351181030273
2011	44.52294921875
2012	44.0791702270508
2013	44.7707099914551
2014	45.0922813415527
2015	46.1443901062012
2016	45.5429801940918
2017	46.1451187133789
2018	46.2240905761719
2019	47.010799407959
2020	45.79248046875