Year	% gross
1970	5.14332008361816
1971	5.10164022445679
1972	5.05911016464233
1973	5.09876012802124
1974	5.24243021011353
1975	6.02874994277954
1976	7.43918991088867
1977	8.28654956817627
1978	8.31984996795654
1979	8.7923002243042
1980	8.78905963897705
1981	8.50072002410889
1982	8.98900985717773
1983	8.95398998260498
1984	9.53652954101563
1985	8.56999969482422
1986	8.89023017883301
1987	9.12642955780029
1988	9.0062198638916
1989	9.56754970550537
1990	9.87833976745605
1991	10.1858501434326
1992	10.2800798416138
1993	9.92671012878418
1994	9.88739967346191
1995	10.1630897521973
1996	10.8015203475952
1997	11.5467395782471
1998	12.5513000488281
1999	12.3674097061157
2000	13.3278503417969
2001	13.7764596939087
2002	14.50465965271
2003	15.4293298721313
2004	16.419319152832
2005	17.7973194122314
2006	20.4164905548096
2007	20.5871696472168
2008	21.6312198638916
2009	23.770809173584
2010	24.4515209197998
2011	24.3813705444336
2012	24.0696792602539
2013	24.0367202758789
2014	26.9629707336426
2015	27.6842498779297
2016	27.992359161377
2017	28.8724803924561
2018	29.3789100646973
2019	30.6177406311035
2020	31.2311496734619