Year	% gross
1981	16.1475296020508
1987	20.7345695495605
1988	20.6704597473145
1989	19.8546199798584
1990	18.2600803375244
1991	17.5597095489502
1992	17.5561790466309
1993	18.3133792877197
1994	18.3217906951904
1995	18.8627109527588
1996	20.2056407928467
1997	19.7296905517578
1998	18.5982303619385
1999	19.7568702697754
2000	20.2894401550293
2001	22.651029586792
2002	22.6512393951416
2003	23.1780796051025
2004	23.4277496337891
2005	23.5163192749023
2006	24.631160736084
2008	19.3940505981445
2009	21.6561908721924
2010	22.2077903747559
2011	25.12672996521
2012	30.4716091156006
2013	32.5793190002441
2014	33.3226699829102
2015	33.4952507019043
2016	33.7213287353516
2017	32.614070892334
2018	36.1220703125
2019	37.3905410766602
2020	35.4792289733887
