Year	% gross
1971	12.590669631958
1975	16.0825691223145
1976	17.2868595123291
2013	25.993709564209
2014	27.1781902313232
2015	29.5762710571289
2016	28.0940246582031
2017	28.1678085327148
2018	29.6392498016357
2019	7.11577701568604
2020	5.87380075454712
2021	6.3404746055603