Year	% gross
1971	3.41232991218567
1972	4.05108022689819
1973	5.54326009750366
1974	7.48788976669312
1976	20.3679008483887
1977	23.0119590759277
1978	22.9666004180908
1979	23.5935001373291
1980	21.4889793395996
1981	15.9201898574829
1982	14.7219896316528
1983	13.1975603103638
1984	13.0548696517944
1985	11.0357303619385
1986	9.46041011810303
2007	16.8377895355225
2023	19.2384796142578
