Year	% gross
1970	7.05265998840332
1971	7.40075016021729
1972	8.09794044494629
1973	8.39696025848389
1974	8.51751041412354
1975	8.8587703704834
1976	8.99738025665283
1977	9.15431022644043
1978	9.06039047241211
1979	8.68185043334961
1980	9.175950050354
1981	15.1057596206665
1982	21.9551105499268
1983	28.8789196014404
1984	36.5178108215332
1985	40.4560317993164
1986	43.3088493347168
1987	44.925350189209
1988	46.0019989013672
1989	46.3060989379883
1990	43.7634391784668
1991	45.2572288513184
1992	40.4357414245605
1993	38.262939453125
1994	38.8345603942871
1995	40.470401763916
1996	41.035888671875
1997	42.3502311706543
1999	41.3983001708984
2000	41.6025581359863
2001	43.313549041748
2002	42.3983192443848
2003	40.0485382080078
2012	52.5131912231445
2013	51.8495788574219