Year	% gross
1972	10.6598501205444
1973	10.6278295516968
1974	10.7102003097534
1975	11.1717796325684
1976	12.9723501205444
1977	16.5367298126221
1978	15.2072696685791
1979	15.426139831543
1980	16.5378799438477
1981	18.0083599090576
1982	18.360969543457
1983	19.3194599151611
1984	20.2178802490234
1985	21.5312900543213
1986	22.8435802459717
1987	24.2406005859375
1988	25.1060905456543
1989	24.9811191558838
1990	24.8771591186523
1991	24.6116695404053
1992	24.9615097045898
1993	25.0507297515869
1994	24.880220413208
1995	25.357349395752
1996	25.7896308898926
1997	24.119909286499
1998	27.0059108734131
1999	27.6533393859863
2000	28.6478900909424
2001	29.1516895294189
2002	28.8700695037842
2003	29.9044704437256
2004	31.4370002746582
2005	33.0520401000977
2006	35.6463584899902
2007	37.2728805541992
2008	39.0863189697266
2009	40.9064788818359
2010	42.774169921875
2011	45.6095581054688
2012	48.8515281677246
2013	50.8464393615723
2014	51.2443199157715
2015	53.128231048584
2016	54.8894386291504
2017	56.7389183044434
2018	57.7445182800293
2019	58.5595512390137
2020	58.8038711547852