Year	% gross
1971	10.8405504226685
1972	11.1979398727417
1973	11.1479501724243
1974	11.4106597900391
1975	11.5575399398804
1976	11.6777696609497
1977	11.793140411377
1978	11.9594602584839
1979	12.6620101928711
1980	13.3049802780151
1981	13.9946699142456
1982	14.527440071106
1983	14.5739698410034
1984	14.4406204223633
1985	14.6846704483032
1986	14.4699602127075
1987	13.9511604309082
1988	13.6825399398804
1989	13.3118000030518
1990	13.8613996505737
1991	13.9361801147461
1992	14.4313802719116
1993	15.5901899337769
1994	17.9122791290283
1995	19.9913501739502
1996	21.3941402435303
1997	23.0704097747803
1998	26.4753704071045
1999	29.5665798187256
2000	34.0489196777344
2001	37.3515815734863
2002	41.2843818664551
2003	46.2099304199219
2004	51.5099792480469
2005	53.0367698669434
2006	54.2730903625488
2007	54.3673706054688
2008	52.8222503662109
2009	52.4678382873535
2010	51.7181396484375
2011	51.757381439209
2012	52.5451507568359
2013	49.937931060791
2014	46.0961799621582
2015	44.3338088989258
2016	43.9916191101074
2017	44.4259490966797
2018	45.6459808349609
2019	46.8023986816406
2020	48.6832885742188
2021	50.4345512390137