Year	% gross
1970	10.4948902130127
1971	10.329400062561
1972	10.2206497192383
1973	10.1900501251221
1974	10.2820997238159
1975	10.7478504180908
1976	12.5122995376587
1977	16.0006198883057
1978	14.7394599914551
1979	14.9826002120972
1980	16.1027297973633
1981	17.5305404663086
1982	17.911319732666
1983	18.8112907409668
1984	19.6769695281982
1985	20.8311901092529
1986	22.1921997070313
1987	23.6208190917969
1988	24.3962993621826
1989	24.2844791412354
1990	24.1707496643066
1991	24.0522804260254
1992	24.3224906921387
1993	24.4057197570801
1994	24.2492694854736
1995	24.7303905487061
1996	25.184700012207
1997	23.6091194152832
1998	26.4905109405518
1999	27.0853805541992
2000	28.0876502990723
2001	28.6812400817871
2002	28.498420715332
2003	29.5341796875
2004	31.0876693725586
2005	32.7555809020996
2006	35.3190612792969
2007	36.9044494628906
2008	38.7390403747559
2009	40.5265808105469
2010	42.5109901428223
2011	45.4096412658691
2012	48.6827812194824
2013	50.7515907287598
2014	51.0689697265625
2015	52.8863105773926
2016	54.6213912963867
2017	56.4637184143066
2018	57.4628105163574
2019	58.2619514465332
2020	58.2929916381836