Year	% gross
1972	7.8116397857666
1973	7.77476978302002
1974	7.89612007141113
1975	8.02256965637207
1976	8.15225028991699
1977	8.27007961273193
1978	8.54199028015137
1979	8.74104022979736
1980	9.02649021148682
1981	9.02877044677734
1982	9.03355979919434
1983	9.05949020385742
1984	9.14126968383789
1985	9.21568012237549
1986	9.30848026275635
1987	9.63304042816162
1988	9.77851009368896
1989	9.72622966766357
1990	9.87036991119385
1991	9.93914985656738
1992	9.91077041625977
1993	9.99557018280029
1994	9.88601016998291
1995	9.93787956237793
1996	10.0768404006958
1997	10.0775995254517
1998	10.3226499557495
1999	10.6069402694702
2000	11.3447599411011
2001	11.4034204483032
2002	11.7689199447632
2003	12.1975202560425
2004	12.6393203735352
2005	12.9236297607422
2006	13.8737802505493
2007	14.5518598556519
2008	15.727219581604
2009	17.012020111084
2010	16.8338108062744
2011	17.4657897949219
2012	19.8519992828369
2013	20.5467090606689
2014	21.5653991699219
2015	22.942720413208
2016	24.2084293365479
2017	24.8187198638916
2018	24.8505592346191
2019	25.2221603393555
2020	26.0790004730225