Year	% gross
1971	0.511189997196198
1972	0.643599987030029
1973	0.815739989280701
1974	0.967079997062683
1975	1.09335994720459
1979	1.63155996799469
1980	1.8162100315094
1981	1.57825994491577
1982	1.61678004264832
1983	1.73670995235443
1984	1.94271004199982
1985	2.13028001785278
1987	2.38243007659912
1988	2.54451990127563
1989	2.53525996208191
1990	2.89053988456726
1991	3.18982005119324
1999	4.94548988342285
2000	4.68230009078979
2001	4.69813013076782
2002	5.12341976165771
2003	5.17119979858398
2004	5.16341018676758
2005	5.95094013214111
2006	6.95722007751465
2007	7.42952013015747
2008	8.04526042938232
2009	9.20979022979736
2010	11.3307199478149
2011	12.2482299804688
2012	13.2559003829956
2013	15.4463300704956
2014	16.4135303497314
2015	16.9564609527588
2016	12.45934009552
2017	12.7472696304321
2018	14.3037796020508