Year	% gross
1973	3.32074999809265
1974	3.31752991676331
1975	3.58222007751465
1976	6.37982988357544
1977	12.5694103240967
1978	9.1791296005249
1979	8.75306034088135
1980	10.3075504302979
1981	13.1897802352905
1982	13.1081199645996
1983	14.1586503982544
1984	15.2735795974731
1985	17.2976398468018
1986	19.5453300476074
1987	21.0209007263184
1988	22.6110095977783
1989	22.4200096130371
1990	21.5611095428467
1991	22.067440032959
1992	23.0196990966797
1993	23.8674697875977
1994	24.4118099212646
1995	25.4661998748779
1996	26.5277309417725
1997	27.8724193572998
1998	37.8562316894531
1999	40.8056106567383
2000	40.7685089111328
2001	40.8813018798828
2002	38.0327186584473
2003	38.0482902526855
2004	38.8613586425781
2005	40.0553894042969
2006	42.5063591003418
2007	45.0992393493652
2008	47.342601776123
2009	50.0452499389648
2010	52.364070892334
2011	57.2891616821289
2012	64.5166931152344
2013	68.5827331542969
2014	71.5893707275391
2015	73.8935928344727
2016	76.9151763916016
2017	79.042350769043
2018	82.1584701538086
2019	82.7378921508789
2020	82.8611373901367