Year	% gross
1971	100.263252258301
1972	100.862373352051
1973	101.90055847168
1974	105.26953125
1975	106.919509887695
1976	108.73388671875
1977	107.399261474609
1978	103.213737487793
1979	101.485961914063
1980	101.572731018066
1981	103.752197265625
1982	106.462928771973
1983	108.527313232422
1984	110.634902954102
1985	111.973342895508
1986	111.92488861084
1987	108.063049316406
1988	104.943382263184
1989	102.979019165039
1990	103.713516235352
1991	104.573143005371
1992	111.047332763672
1993	114.398597717285
1994	117.056121826172
1995	117.602470397949
1996	116.684692382813
1999	107.687652587891
2000	109.065773010254
2001	110.269020080566
2002	112.277740478516
2003	114.152381896973
2004	115.394630432129
2005	118.994979858398
2006	118.444488525391
2007	117.556396484375
2008	117.501480102539
2009	118.163963317871
2010	119.043060302734
2011	120.444267272949
2012	119.76944732666
2013	118.452041625977
2014	117.747886657715
2015	116.602447509766
2016	115.897552490234
2017	115.023628234863
2018	114.225379943848
2019	113.878143310547
2020	113.197746276855