Year	% gross
1973	0.214980006217957
1974	0.238529995083809
1975	0.230540007352829
1976	0.258190006017685
1977	0.229699999094009
1978	0.413159996271133
1979	0.452329993247986
1980	0.596989989280701
1981	0.434630006551743
1982	0.441980004310608
1983	0.442589998245239
1984	0.474620014429092
1985	0.552269995212555
1986	0.570190012454987
1987	0.650940001010895
1989	1.23877000808716
1990	1.37945997714996
1991	1.44131994247437
1992	1.56958997249603
1993	1.45348000526428
1995	1.08616995811462
1996	0.983699977397919
1997	1.08649003505707
1998	1.14731001853943
1999	1.07922995090485
2000	0.929740011692047
2001	1.06939995288849
2002	1.28849005699158
2003	1.3578200340271
2004	1.36794996261597
2005	1.40991997718811
2006	1.68874001502991
2007	1.89021003246307
2008	2.36385011672974
2009	2.93281006813049
2010	3.96690988540649
2011	5.43135976791382
2012	5.97153997421265
2013	6.91351985931396
2014	7.07096004486084
2015	7.34412002563477
2016	7.85291004180908
2017	7.91909980773926
2018	8.04769992828369
2019	7.39225006103516
2020	7.41352987289429
2021	7.02583980560303