Year	% gross
1971	11.7859296798706
1972	14.1336803436279
1973	13.8773603439331
1974	14.5329704284668
1975	15.5139799118042
1976	15.7245197296143
1977	18.8026008605957
1978	19.8781795501709
1979	21.6137409210205
1980	20.2084102630615
1981	23.6364498138428
1982	22.5867099761963
1983	22.603910446167
1984	22.1344509124756
1985	22.938440322876
1986	22.5094699859619
1987	21.66090965271
1988	23.2518100738525
1989	21.9302101135254
1990	21.0903491973877
1991	20.8463802337646
1992	19.6618404388428
1993	19.3371105194092
1994	17.6523990631104
1995	16.9827995300293
2002	13.5268602371216
2003	13.9681301116943
2004	16.4825706481934
2005	19.4422492980957
2006	22.0916900634766
2007	23.2987594604492
2008	23.6695804595947
2009	24.6621704101562
2010	27.6193294525146
2011	25.8015804290771
2012	30.6684494018555
2013	33.236141204834
2014	46.5207214355469
2015	48.1562194824219
2016	42.9232406616211
