Year	% gross
1970	2.05663990974426
1971	2.13837003707886
1972	2.57938003540039
1973	2.82488989830017
1974	3.35041999816895
1975	3.80048990249634
1976	3.77752995491028
1977	3.73866009712219
1978	3.66360998153687
1979	4.68207979202271
1980	4.42235994338989
1981	5.64434003829956
1982	4.5497899055481
1983	4.22516012191772
1984	4.12841987609863
1985	4.353759765625
1986	4.36985015869141
1987	4.67501020431519
1988	4.95523023605347
1989	5.21093988418579
1990	6.69261980056763
1991	8.08366012573242
1992	8.10097980499268
1993	8.11334991455078
1994	8.11166954040527
1995	8.11989974975586
1996	8.12862014770508
1997	8.27694034576416
1998	8.31429958343506
1999	8.50609016418457
2000	8.30165004730225
2001	8.30770969390869
2002	8.51237010955811
2003	8.57861995697021
2004	8.6014404296875
2005	8.60122013092041
2006	9.54860019683838
2007	10.4606199264526
2008	11.3263597488403
2009	12.1848201751709
2010	12.9817199707031
2011	13.7553396224976
2012	14.4874401092529
2013	15.1345300674438
2014	15.7028999328613
2015	16.2178401947021
2016	16.7055206298828
2017	17.1407794952393
2018	17.5751304626465
2019	17.9632797241211
2020	18.1105003356934
