Year	% gross
1971	37.8958206176758
1972	37.7494010925293
1974	42.8341407775879
1976	51.7631912231445
1977	50.616569519043
1978	48.3382186889648
1979	48.2015495300293
1980	48.5948905944824
1981	52.4450492858887
1982	52.711540222168
1983	54.6056518554688
1984	56.6238288879395
1985	57.3140106201172
1986	61.1959190368652
1987	62.044189453125
1988	61.6954307556152
1989	60.4845008850098
1990	60.959789276123
1991	65.0517883300781
1995	69.5888900756836
1996	71.1154403686523
2005	70.5173263549805
2013	71.5239562988281
2014	64.7829437255859
2015	72.0273590087891
2016	71.937370300293
2017	72.93408203125
2018	72.1459197998047
2019	72.2141723632813
2020	72.3956832885742