Year	% gross
1972	14.8807096481323
1973	15.2317895889282
1974	15.5898504257202
1975	16.9465408325195
1976	17.5912208557129
1977	18.1260299682617
1978	18.9303703308105
1979	18.7742595672607
1980	19.023099899292
1981	17.2890892028809
1982	17.4472599029541
1983	17.6758899688721
1984	17.7859401702881
1985	17.7826690673828
1986	17.686710357666
1987	17.7465896606445
1988	17.723180770874
1989	17.6966304779053
1990	17.6147193908691
1991	17.4642391204834
1992	17.1534595489502
1993	16.5945301055908
1994	16.0564708709717
1995	15.7648897171021
1996	15.6976203918457
1997	14.8699398040771
1998	14.9440698623657
1999	12.5825901031494
2000	12.8031797409058
2001	12.6887798309326
2002	13.2086801528931
2003	14.2537899017334
2004	15.2977304458618
2005	15.5662899017334
2006	16.131929397583
2007	16.6571807861328
2008	16.4170093536377
2009	18.1406803131104
2010	17.4688396453857
2011	19.8334693908691
2012	24.8032093048096
2013	26.7833805084229
2014	19.4220600128174
2015	21.022180557251
2016	20.9843902587891
2017	21.4729900360107
2018	21.6704807281494
2019	21.8293304443359
2020	21.8901195526123