Year	% gross
1971	57.254711151123
1972	58.9090995788574
1973	62.0154495239258
1974	65.1647796630859
1975	66.8487014770508
1976	69.6773910522461
1977	72.3640670776367
1978	74.4596176147461
1979	76.687370300293
1980	78.9272537231445
1981	80.5461502075195
1982	81.0282669067383
1983	82.4738235473633
1984	83.5308074951172
1985	84.3140029907227
1986	87.2470092773438
1987	88.9009323120117
1988	88.3531875610352
1989	87.9240798950195
1990	90.9082336425781
1991	91.7191696166992
1992	92.4135208129883
1993	93.8306579589844
1994	94.5656585693359
1995	94.2600326538086
1996	94.4867324829102
1997	95.8931274414063
1998	96.3698806762695
1999	96.8298034667969
2000	97.9613876342773
2001	97.6501083374023
2002	99.2470092773438
2003	101.004287719727
2004	102.211441040039
2005	101.359710693359
2006	100.907852172852
2007	99.4227676391602
2008	98.6516723632813
2009	97.361930847168
2010	98.718391418457
2011	98.8527908325195
2012	98.719612121582
2013	97.8568115234375
2014	96.3320693969727
2015	95.7180786132813
2016	94.8378524780273
2017	92.8333435058594
2018	92.1619033813477
2019	91.9105606079102
2020	91.8287734985352