Year	% gross
1970	10.2286100387573
1971	6.8620400428772
1972	7.29208993911743
1973	10.0929002761841
1975	10.6076002120972
1976	10.8395795822144
1977	10.9981603622437
1978	11.0314702987671
1979	12.3180704116821
1980	13.0340099334717
1981	13.9922103881836
1982	14.5582399368286
1983	15.6491804122925
1984	16.5031509399414
1985	17.0625896453857
1986	17.2431201934814
1987	18.048059463501
1988	18.6904106140137
1989	19.1225395202637
1990	18.9165802001953
1991	18.7614593505859
1992	19.5595798492432
1993	20.3652191162109
1994	22.0614604949951
1996	23.7470092773438
1997	24.9056205749512
1998	23.909969329834
1999	25.4540596008301
2000	25.8505992889404
2001	27.7937107086182
2002	28.5688304901123
2003	29.3479900360107
2004	31.6313495635986
2005	33.4735908508301
2006	34.413818359375
2007	36.1666603088379
2008	38.2828788757324
2009	41.0744705200195
2010	44.8403816223145
2011	47.0946083068848
2012	48.9813690185547
2013	48.52001953125
2014	48.8418502807617
2015	50.3755187988281
2016	48.5976715087891
2017	51.210750579834