Year	% gross
1970	1.77347004413605
1971	1.80289995670319
1972	1.89796996116638
1973	2.01175999641418
1974	2.08192992210388
1975	2.16982007026672
1976	2.23954010009766
1977	2.36630010604858
1978	2.50600004196167
1979	2.68431997299194
1980	2.84998989105225
1981	3.03785991668701
1982	3.2091600894928
1983	3.28234004974365
1984	3.35567998886108
1985	3.59980988502502
1986	3.72418999671936
1987	3.60574007034302
1988	3.82795000076294
1989	4.026939868927
1990	4.09538984298706
1991	4.16737985610962
1992	4.21949005126953
1993	4.30913019180298
1994	4.37610006332397
1995	4.38000011444092
1996	4.42561006546021
1997	4.49706983566284
1998	4.50822019577026
1999	4.52852010726929
2000	5.00855016708374
2001	5.48674011230469
2002	5.93779993057251
2003	6.45371007919312
2004	6.74700021743774
2005	7.16825008392334
2006	7.38282012939453
2007	7.57462978363037
2008	7.97371006011963
2009	8.36429023742676
2010	8.6690502166748
2011	9.13992977142334
2012	9.52651023864746
2013	9.94272041320801
2014	10.224479675293
2015	10.2831001281738
2016	10.2632904052734
2017	10.3054895401001
2018	10.341329574585
2019	10.2607698440552
2020	10.575590133667
2021	10.3826999664307