Year	% gross
1970	3.68199992179871
1971	3.66001009941101
1972	3.73416996002197
1973	3.90189003944397
1974	4.16786003112793
1975	4.37660980224609
1976	4.465980052948
1977	4.5908899307251
1978	4.70260000228882
1979	4.70165014266968
1980	4.67055988311768
1981	4.82583999633789
1982	4.90972995758057
1983	4.96471977233887
1984	5.09835004806519
1985	5.19133996963501
1986	5.26984977722168
1987	5.2592601776123
1988	5.31228017807007
1989	5.24322986602783
1990	5.17163991928101
1991	5.07352018356323
1992	4.89167976379395
1993	4.73001003265381
1994	4.47433996200562
1995	4.3338098526001
1996	4.22017002105713
1997	4.14108991622925
1998	4.21834993362427
1999	4.32597017288208
2000	4.54087018966675
2001	4.76073980331421
2002	4.9500298500061
2003	5.0933198928833
2004	5.43197011947632
2005	5.80935001373291
2006	6.18973016738892
2007	6.42637014389038
2008	6.8878698348999
2009	7.48129987716675
2010	8.00876998901367
2011	8.16623973846436
2012	8.54992008209229
2013	8.70680046081543
2014	9.07678031921387
2015	9.03355026245117
2016	8.87283039093018
2017	8.96395015716553
2018	9.05842971801758
2019	9.19748020172119
2020	9.39885997772217
