Year	% gross
1972	7.54080009460449
1973	7.59371995925903
1974	7.66486978530884
1975	7.7866997718811
1976	7.89492988586426
1977	7.96870994567871
1978	8.03680038452148
1979	8.16734981536865
1980	8.19577980041504
1981	8.11091995239258
1982	8.23736953735352
1983	8.12726020812988
1984	8.02414035797119
1985	8.08586978912354
1986	8.10087966918945
1990	8.3918399810791
1991	8.32188034057617
1992	8.18397998809814
1993	8.10836029052734
1994	7.882080078125
1995	7.80757999420166
1996	7.81400012969971
1997	7.75494003295898
1998	8.04732036590576
1999	8.17984008789063
2000	8.38992023468018
2001	8.50387001037598
2002	8.75450992584229
2003	9.06923007965088
2004	9.32594013214111
2005	9.6086597442627
2006	9.99586963653564
2007	10.2228002548218
2008	10.8905696868896
2009	11.7975101470947
2010	11.4857597351074
2011	11.9456100463867
2012	14.4536104202271
2013	15.1119899749756
2014	16.1752796173096
2015	17.5116996765137
2016	18.0579109191895
2017	18.9800491333008
2018	19.4095802307129
2019	19.8100490570068
2020	20.1125106811523