Year	gross (GPI)
1971	0.578909993171692
1972	0.582499980926514
1973	0.592090010643005
1975	0.599870026111603
1976	0.603519976139069
1977	0.607659995555878
1978	0.600009977817535
1980	0.610979974269867
1981	0.618969976902008
1982	0.615899980068207
1983	0.640160024166107
1984	0.627759993076324
1986	0.657949984073639
1987	0.668169975280762
1988	0.677860021591187
1989	0.675429999828339
1993	0.740249991416931
1994	0.753220021724701
1995	0.754369974136353
1996	0.762629985809326
1997	0.775860011577606
1999	0.796970009803772
2000	0.802240014076233
2001	0.809880018234253
2002	0.830370008945465
2003	0.915700018405914
2007	0.942560017108917
2008	0.967050015926361
2009	0.989970028400421
2010	0.989049971103668
2011	0.998529970645905
2012	1.00339996814728
2013	1.03569304943085
2014	1.03251755237579
2015	1.03027153015137
2016	1.03045177459717
2017	1.08402001857758
2018	1.01533448696136
2019	1.01977431774139
2020	1.00732743740082
2021	0.991640269756317