Year	% gross
1970	9.58767986297607
1971	9.50168037414551
1972	9.46627044677734
1973	9.39095973968506
1974	9.41761016845703
1975	10.5328702926636
1976	12.2254800796509
1977	13.0568504333496
1978	13.4263896942139
1979	14.1665000915527
1980	14.3191404342651
1981	14.3948202133179
1982	14.3621597290039
1983	14.2413101196289
1984	14.614049911499
1985	14.0132503509521
1986	13.8299703598022
1987	14.0100498199463
1988	13.9872102737427
1989	14.5455198287964
1990	14.6023397445679
1991	14.9427604675293
1992	15.2288999557495
1993	14.5808200836182
1994	14.5039796829224
1995	14.691840171814
1996	15.2410497665405
1997	15.9518203735352
1998	16.9914093017578
1999	16.2468109130859
2000	16.9215106964111
2001	16.9498500823975
2002	17.4793090820313
2003	17.829870223999
2004	18.6181907653809
2005	19.8658199310303
2006	22.3737201690674
2007	22.1685199737549
2008	23.7679901123047
2009	25.413480758667
2010	26.8091506958008
2011	25.574369430542
2012	25.4355907440186
2013	25.2576293945313
2014	28.1061496734619
2015	29.0003108978271
2016	28.7452793121338
2017	29.6247901916504
2018	29.9424304962158
2019	31.0680103302002
2020	31.4863700866699