Year	gross (GPI)
1970	0.999260008335114
1971	0.99957001209259
1972	1.00133001804352
1973	1.01425004005432
1974	0.998040020465851
1975	0.99888002872467
1976	1.01442003250122
1977	0.996529996395111
1978	0.997030019760132
1979	0.994029998779297
1980	0.996969997882843
1981	0.997150003910065
1982	0.997529983520508
1983	0.997380018234253
1984	0.996900022029877
1985	0.993409991264343
1986	0.992160022258759
1987	0.994750022888184
1988	0.989820003509521
1989	0.992259979248047
1990	0.994780004024506
1991	0.995800018310547
1992	0.995050013065338
1993	0.995630025863647
1994	0.992500007152557
1995	0.986500024795532
1996	0.986259996891022
1997	0.989090025424957
1998	0.987800002098084
1999	0.988250017166138
2000	0.990209996700287
2001	0.990549981594086
2002	0.987169981002808
2003	0.987919986248016
2004	0.989040017127991
2005	0.987720012664795
2006	0.987020015716553
2007	0.988300025463104
2008	0.987800002098084
2009	0.989759981632233
2010	0.990580022335052
2011	0.992280006408691
2012	0.994700014591217
2013	0.996940016746521
2014	0.997219979763031
2015	0.99795001745224
2016	0.999620020389557
2017	0.995580017566681
2018	0.995869994163513
2019	0.999000012874603
2020	1.00113999843597