Year	% gross
1970	22.8369903564453
1971	24.4357604980469
1972	26.0887203216553
1973	28.6568908691406
1974	30.7816791534424
1975	35.0034599304199
1976	37.1095085144043
1977	38.7118606567383
1981	41.4832992553711
1982	43.3603210449219
1983	44.3607711791992
1984	47.4165496826172
1985	49.7630386352539
1986	52.1736106872559
1987	57.0039482116699
1988	59.4472312927246
1996	51.0307807922363
1997	52.6756401062012
1998	54.2167587280273
1999	54.8812789916992
2000	58.2250595092773
2001	59.093578338623
2002	59.7667808532715
2003	60.280689239502
2004	61.8919296264648
2005	63.1800498962402
2006	63.2057495117188
2007	64.0615081787109
2008	65.937858581543
2009	67.4372100830078
2010	68.3803863525391
2011	68.336669921875
2012	69.9600296020508
2013	71.6748733520508
2014	72.6628799438477
2015	74.1502685546875
2016	74.7822570800781
2017	75.5577697753906
2018	76.6059875488281
2019	77.2228698730469
2020	75.6821975708008