Year	% gross
1980	15.1594800949097
1981	15.1340103149414
1982	15.1646404266357
1983	15.0375299453735
1984	14.9231100082397
1985	14.8477697372437
1986	14.9920997619629
1987	15.0718603134155
1988	15.2239198684692
1989	15.4038200378418
1990	15.4319400787354
1991	15.28005027771
1992	15.3002901077271
1993	15.1274499893188
1994	14.8388500213623
1995	14.8053798675537
1996	14.8572301864624
1997	14.7907495498657
1998	14.5519599914551
1999	13.2698097229004
2000	14.1042098999023
2001	14.7350797653198
2002	15.8702402114868
2003	17.8766403198242
2004	19.7306709289551
2005	20.8424301147461
2006	22.1822395324707
2007	20.0172805786133
2008	19.104679107666
2009	19.8505306243896
2010	20.5449295043945
2011	22.9387607574463
2012	24.926139831543
2013	27.712760925293
2014	20.4542007446289
2015	21.7492904663086
2016	23.1048603057861
2017	23.4570598602295
2018	23.3111991882324
2019	23.4432601928711
2020	24.1554203033447