Year	% gross
1971	4.48003005981445
1972	4.58124017715454
1973	4.96611022949219
1974	5.31915998458862
1975	5.97459983825684
1976	6.63875007629395
1977	7.29159021377563
1978	8.15050983428955
1979	8.81359004974365
1980	8.6841402053833
1981	6.90111017227173
1982	7.95010995864868
1983	7.19218015670776
1984	7.2708101272583
1985	6.55705976486206
1987	5.85029983520508
1988	5.93529987335205
1989	6.52812004089355
1990	6.43826007843018
1991	6.8669900894165
1992	7.80359983444214
1993	7.86525011062622
1994	8.95944976806641
1995	10.0313301086426
1996	10.5547704696655
1997	11.4335699081421
1998	12.3766298294067
1999	13.9309396743774
2000	16.063570022583
2003	20.3113403320312
2004	22.1290702819824
2005	23.9585609436035
2006	25.9403591156006
2007	28.5298690795898
2008	31.969669342041
2009	35.0469512939453
2010	37.7953300476074
2011	39.9008598327637
2013	40.4660987854004
2014	42.4749717712402
2015	40.1157302856445
2016	41.2106895446777
2017	39.5736885070801
2018	38.9281616210938
2020	35.3619995117188