Year	gross (GPI)
1971	0.986570000648499
1972	0.992079973220825
1973	0.993820011615753
1974	0.996129989624023
1975	1.00046002864838
1976	0.984040021896362
1977	0.9964399933815
1978	0.986429989337921
1979	0.985220015048981
1980	0.984359979629517
1981	0.993120014667511
1982	0.995989978313446
1983	0.995800018310547
1984	0.99685001373291
1985	0.995700001716614
1986	0.995580017566681
1987	0.993080019950867
1988	0.993680000305176
1989	0.990260004997253
1990	0.99167001247406
1991	0.994490027427673
1992	0.995500028133392
1993	0.992950022220612
1994	0.997579991817474
1995	0.994859993457794
1996	0.988250017166138
1997	0.990040004253387
1998	0.981289982795715
1999	0.979120016098022
2000	0.976970016956329
2001	0.977280020713806
2002	0.978349983692169
2003	0.978460013866425
2004	0.968940019607544
2005	0.967949986457825
2006	0.968990027904511
2007	0.969049990177155
2008	0.977050006389618
2009	0.976559996604919
2010	0.97026002407074
2011	0.966310024261475
2012	0.969579994678497
2013	0.966939985752106
2014	0.97460001707077
2015	0.97545999288559
2016	0.976230025291443
2017	0.980499982833862
2018	0.97681999206543
2019	0.985469996929169
2020	0.983699977397919