Year	% gross
1971	107.302917480469
1972	107.691291809082
1973	107.39900970459
1974	106.801429748535
1975	106.178611755371
1976	105.340682983398
1977	104.665298461914
1978	103.767196655273
1979	102.578262329102
1980	102.212280273438
1981	101.026229858398
1982	100.47998046875
1983	100.332260131836
1984	100.518356323242
1985	100.646697998047
1986	100.605651855469
1987	100.684059143066
1988	100.857246398926
1989	100.288543701172
1990	100.610877990723
1991	100.505340576172
1992	103.512962341309
1993	104.68514251709
1994	103.81974029541
1995	103.38516998291
1996	104.164741516113
1997	104.03076171875
1998	103.657897949219
1999	103.815231323242
2000	102.286979675293
2001	101.997718811035
2002	102.74291229248
2003	103.363838195801
2004	103.984832763672
2005	103.975090026855
2006	103.77806854248
2007	103.754119873047
2008	102.942352294922
2009	101.48217010498
2010	100.803382873535
2011	100.301696777344
2012	100.027786254883
2013	101.110427856445
2014	100.750701904297
2015	100.370170593262
2016	99.8108978271484
2017	102.801086425781
2018	102.892997741699
2019	102.957496643066
2020	102.634689331055
2021	101.617156982422