Year	% gross
1972	1.21650004386902
1973	1.24605000019073
1974	1.18756997585297
1975	1.27419996261597
1976	1.80472004413605
1977	2.0324399471283
1978	2.17105007171631
1979	2.20998001098633
1980	2.49202990531921
1981	3.20531988143921
1982	2.81600999832153
1983	2.55564999580383
1984	2.53899002075195
1987	3.45641994476318
1988	3.829430103302
1990	3.9073600769043
1991	4.28594017028809
1992	4.82733011245728
1993	4.05135011672974
1994	4.38626003265381
1995	4.90105009078979
1996	4.77051019668579
1998	5.29268980026245
2011	14.6202096939087
2012	16.121789932251
2013	15.8141899108887
2014	15.0526504516602
2015	15.3406600952148
2016	16.9067993164062
2017	17.0065402984619
2018	17.3759994506836
2019	17.3384494781494
2020	19.1300601959229