Year	% gross
1974	9.305100440979
1975	9.71393966674805
1976	11.4314603805542
1977	14.8632297515869
1978	13.6015195846558
1979	13.8399200439453
1980	14.9383001327515
1981	16.3026790618896
1982	16.7269897460938
1983	17.5863800048828
1984	18.4512100219727
1985	19.4311103820801
1986	20.8533191680908
1987	22.3614406585693
1988	23.0793991088867
1989	23.0008697509766
1990	22.9029693603516
1991	22.9964008331299
1992	23.2107791900635
1993	23.3188095092773
1994	23.1977996826172
1995	23.6675605773926
1996	24.152660369873
1997	22.6762199401855
1998	25.5182704925537
1999	26.1319007873535
2000	27.1207599639893
2001	27.8008708953857
2002	27.7102699279785
2003	28.750919342041
2004	30.3454093933105
2005	32.0407104492188
2006	34.5725288391113
2007	36.1128082275391
2008	37.9367485046387
2009	39.6553115844727
2010	41.7403793334961
2011	44.7209014892578
2012	48.0632019042969
2013	50.2617683410645
2014	50.509449005127
2015	52.263111114502
2016	54.0342788696289
2017	55.8991317749023
2018	56.8708305358887
2019	57.6268501281738
2020	57.425651550293