Year	% gross
1971	22.1853694915771
1972	23.6967792510986
1973	25.1985397338867
1974	27.1974105834961
1975	26.5848293304443
1976	26.4559001922607
1977	26.6840591430664
1978	25.9774208068848
1979	26.4720897674561
1980	26.5873107910156
1981	26.1785907745361
1982	26.8347301483154
1983	28.5555801391602
1984	28.8205394744873
1985	28.8725605010986
1986	27.3928394317627
1987	30.120569229126
1988	28.8672904968262
1989	30.6851196289062
1990	34.8007507324219
1991	39.0575408935547
1992	42.0146484375
1993	45.8890495300293
1994	49.6022911071777
1995	48.8796882629395
1996	52.1915016174316
1997	54.8201484680176
1998	55.2459106445312
1999	56.9094581604004
2000	57.1540718078613
2001	56.0848999023438
2002	57.3519096374512
2003	61.7021903991699
2004	62.4209213256836
2005	62.3141899108887
2006	61.4239807128906
2007	59.9984588623047
2008	56.4228096008301
2009	55.6394195556641
2010	55.4226913452148
2011	55.3115882873535
2012	55.8396987915039
2013	60.8929710388184
2014	64.1545867919922
2015	64.7038269042969
2016	66.4158477783203
2017	67.5593109130859
2018	69.2033767700195
2019	69.4145202636719
2020	70.1601409912109
2021	75.4320373535156
