Year	% gross
1970	7.41757011413574
1971	7.35357999801636
1972	7.31444978713989
1973	7.29496002197266
1974	7.37855005264282
1975	8.33323955535889
1976	9.88854026794434
1977	10.7277097702026
1978	10.9332103729248
1979	11.5427503585815
1980	11.6191501617432
1981	11.5168504714966
1982	11.7386903762817
1983	11.6594896316528
1984	12.1341104507446
1985	11.3537197113037
1986	11.4153995513916
1987	11.6218395233154
1988	11.5502099990845
1989	12.1090602874756
1990	12.2899703979492
1991	12.6149597167969
1992	12.8077201843262
1993	12.3055400848389
1994	12.2491598129272
1995	12.4813604354858
1996	13.0740604400635
1997	13.8025798797607
1998	14.8252096176147
1999	14.3538198471069
2000	15.1678400039673
2001	15.4015998840332
2002	16.0279903411865
2003	16.6588306427002
2004	17.5457496643066
2005	18.8571300506592
2006	21.419319152832
2007	21.3977394104004
2008	22.7266998291016
2009	24.6130104064941
2010	25.6602001190186
2011	24.9929904937744
2012	24.7700500488281
2013	24.6629199981689
2014	27.5495090484619
2015	28.3596706390381
2016	28.3788204193115
2017	29.2586803436279
2018	29.6682205200195
2019	30.8489093780518
2020	31.3621692657471