Year	% gross
1970	54.7689590454102
1971	54.846248626709
1972	55.4181709289551
1973	56.6946105957031
1974	57.8700103759766
1975	59.5156097412109
1976	60.2943687438965
1977	61.1392707824707
1978	61.9359092712402
1979	62.208309173584
1980	62.9410400390625
1981	61.574390411377
1982	62.3171882629395
1983	62.9792213439941
1984	63.711181640625
1985	64.6559524536133
1986	65.2971572875977
1987	65.8950729370117
1988	66.3224868774414
1989	66.5374603271484
1990	67.1929092407227
1991	66.5805587768555
1992	65.218017578125
1993	63.7760009765625
1994	60.8567314147949
1995	60.6706008911133
1996	60.980899810791
1997	60.6768989562988
1998	60.2917289733887
1999	58.3379592895508
2000	58.8119087219238
2001	59.8939590454102
2002	61.081859588623
2003	63.251651763916
2004	63.5126304626465
2005	65.5416107177734
2006	66.8232421875
2007	67.9502182006836
2008	69.4525833129883
2009	70.2096405029297
2010	71.3281478881836
2011	72.540397644043
2012	73.2271423339844
2013	72.876838684082
2014	73.4598770141602
2015	74.294677734375
2016	75.3232879638672
2017	75.3843383789063
2018	76.2933807373047
2019	77.1199493408203
2020	78.779167175293
