Year	% gross
1970	8.91950988769531
1971	8.71969985961914
1972	8.59654998779297
1973	8.56301975250244
1974	8.60249042510986
1975	9.06752014160156
1976	11.0358400344849
1977	15.0389404296875
1978	13.475079536438
1979	13.681770324707
1980	14.9423904418945
1981	16.590690612793
1982	17.0282707214355
1983	17.9578800201416
1984	18.9097309112549
1985	20.0777893066406
1986	21.7912693023682
1987	23.5326099395752
1988	24.3060207366943
1989	24.2063007354736
1990	24.0617904663086
1991	24.150260925293
1992	24.4944095611572
1993	24.7517108917236
1994	24.7209491729736
1995	25.5018196105957
1996	26.2114391326904
1997	24.5150299072266
1998	28.9674396514893
1999	29.8621006011963
2000	31.2366790771484
2001	32.5298805236816
2002	32.6877899169922
2003	34.2261505126953
2004	36.0481185913086
2005	38.1629295349121
2006	40.860481262207
2007	42.6798210144043
2008	45.0738105773926
2009	47.6047592163086
2010	50.2811698913574
2011	53.5767288208008
2012	57.5341186523438
2013	59.5377502441406
2014	62.1441383361816
2015	64.1468505859375
2016	66.3096618652344
2017	68.3346786499023
2018	69.7666931152344
2019	70.8553466796875
2020	69.9484481811523
