Year	% gross
1971	3.77975988388062
1972	2.63067007064819
1973	3.06767988204956
1974	2.89581990242004
1975	2.39421010017395
1976	2.66045999526978
1977	2.03892993927002
1978	2.20104002952576
1979	2.52236008644104
1980	2.26769995689392
1981	2.70040011405945
1982	2.99186992645264
1983	3.02463006973267
1984	2.90005993843079
1985	2.84724998474121
1986	2.81890988349915
1987	2.73227000236511
1988	2.85467004776001
1989	2.67576003074646
1990	2.60593008995056
1991	2.84718990325928
1994	2.6219699382782
1995	2.45517992973328
1996	2.48313999176025
1997	2.46586990356445
1998	2.44910001754761
1999	2.61420011520386
2000	2.2019100189209
2001	2.32344007492065
2002	2.63193011283875
2003	2.63343000411987
2004	3.03694009780884
2006	3.81346011161804
2007	4.19182014465332
2008	4.73333978652954
2009	7.27801990509033
2010	7.35999011993408
2011	9.22698020935059
2012	10.8493099212646
2013	13.9732398986816
2014	15.2706098556519
2015	17.8179702758789
2017	21.758150100708
2018	23.1605491638184
2019	25.3545398712158
2020	30.2681407928467
2021	29.7833995819092