Year	% gross
1970	4.17093992233276
1971	4.18824005126953
1972	4.32156991958618
1973	4.46181011199951
1974	4.53902006149292
1975	4.90747976303101
1976	5.55513000488281
1977	5.87122011184692
1978	5.90097999572754
1979	5.91227006912231
1980	5.90286016464233
1981	6.01565980911255
1982	6.19502019882202
1983	5.8165397644043
1984	5.83046007156372
1985	6.13039016723633
1986	6.45936012268066
1987	6.81532001495361
1988	7.10561990737915
1989	7.44684982299805
1990	8.1259298324585
1991	9.19050025939941
1992	9.39441967010498
1993	9.75914001464844
1994	10.3702802658081
1995	10.8483896255493
1996	11.5015802383423
1997	12.1606998443604
1998	12.4047899246216
1999	12.7080698013306
2000	15.960729598999
2001	17.4871006011963
2002	19.0698299407959
2003	20.3253707885742
2004	21.5095691680908
2005	20.7667598724365
2006	20.945240020752
2007	22.6083908081055
2008	24.5318908691406
2009	25.6319808959961
2010	27.7315502166748
2011	27.7870502471924
2012	29.0517807006836
2013	28.9871196746826
2014	28.7765102386475
2015	28.3610706329346
2016	28.6182193756104