Year	% gross
1970	106.537643432617
1971	106.14794921875
1972	106.137657165527
1973	105.930130004883
1974	105.360443115234
1975	105.656127929688
1976	105.09008026123
1977	104.345962524414
1978	104.188819885254
1979	104.469772338867
1980	104.502937316895
1981	103.537933349609
1982	103.81063079834
1983	103.516990661621
1984	104.139678955078
1985	103.874290466309
1986	103.12052154541
1987	103.653343200684
1988	103.371536254883
1989	103.556282043457
1990	104.898231506348
1991	101.11190032959
1992	100.913307189941
1993	101.707008361816
1994	102.089012145996
1995	103.269096374512
1996	100.749069213867
1997	100.401077270508
1998	99.7767181396484
1999	98.4881362915039
2000	98.7025833129883
2001	99.079231262207
2002	99.3193664550781
2003	99.7229309082031
2004	99.3522491455078
2005	99.4135131835938
2006	99.1890563964844
2007	99.1897888183594
2008	99.2470016479492
2009	99.1864318847656
2010	99.1354217529297
2011	99.2023086547852
2012	98.9736328125
2013	98.9489669799805
2014	98.6437530517578
2015	98.5088195800781
2016	98.6423034667969
2017	98.48291015625
2018	98.6775894165039
2019	98.4212417602539
2020	97.6951293945312
2021	98.0676727294922