Year	gross (GPI)
1970	0.996990025043488
1971	0.997770011425018
1972	0.998139977455139
1973	1.00202000141144
1974	0.996819972991943
1975	0.996410012245178
1976	1.0004700422287
1977	0.99686998128891
1978	0.998619973659515
1979	0.99975997209549
1980	1.0022200345993
1981	1.00349998474121
1982	1.00125002861023
1983	0.996290028095245
1984	0.999230027198792
1985	1.0006400346756
1986	0.999400019645691
1987	0.995199978351593
1988	0.993669986724854
1989	0.994310021400452
1990	0.99602997303009
1991	0.993080019950867
1992	0.994019985198975
1993	0.993179976940155
1994	0.995940029621124
1995	0.994249999523163
1996	0.993110001087189
1997	1.00011003017426
1998	1.00660002231598
1999	1.00770998001099
2000	0.993089973926544
2001	0.99728000164032
2002	1.00045001506805
2003	0.997879981994629
2004	0.994719982147217
2005	0.992079973220825
2006	0.998839974403381
2007	0.998350024223328
2008	0.996969997882843
2009	0.998440027236938
2010	0.99769002199173
2011	0.997550010681152
2012	0.997290015220642
2013	0.997420012950897
2014	0.998950004577637
2015	1.00009000301361
2016	0.999790012836456
2017	0.996110022068024
2018	0.998560011386871
2019	1.00250005722046
2020	0.998910009860992