Year	% gross
1972	7.10854005813599
1973	7.09894990921021
1974	7.66885995864868
1975	8.22953987121582
1976	8.8253698348999
1977	9.34815979003906
1978	9.99958992004395
1979	10.5677404403687
1980	11.1347398757935
1981	11.6441097259521
1982	11.8863897323608
1983	12.2378597259521
1984	12.5834703445435
1985	12.9180097579956
1986	13.5094995498657
1987	13.9130296707153
1988	14.3222599029541
1989	13.744930267334
1990	13.139630317688
1991	12.5407400131226
1992	12.1018400192261
1993	11.6198501586914
1994	10.9932098388672
1995	10.5562896728516
1996	10.1951303482056
1997	9.32110977172852
1998	10.8537502288818
1999	10.6114196777344
2000	11.0489101409912
2001	11.5381898880005
2002	11.771369934082
2003	12.1716299057007
2004	12.8208303451538
2005	14.152720451355
2006	15.1110200881958
2007	13.2767200469971
2008	14.0456104278564
2009	14.6772699356079
2010	15.0469198226929
2011	17.3001804351807
2012	19.5311393737793
2013	20.668420791626
2014	21.2001705169678
2015	21.9497394561768
2016	23.5604991912842
2017	24.9309997558594
2018	24.971019744873
2019	25.5738697052002
2020	26.6172409057617