Year	gross (GPI)
1970	0.914550006389618
1971	0.914279997348785
1972	0.913850009441376
1973	0.92808997631073
1974	0.935760021209717
1975	0.950630009174347
1976	0.965520024299622
1977	0.977270007133484
1978	0.992560029029846
1979	0.994889974594116
1980	1.00048005580902
1981	1.00619995594025
1982	1.00241005420685
1983	1.001620054245
1984	1.00173997879028
1985	1.00177001953125
1986	1.00353002548218
1987	1.00260996818542
1988	1.00002002716064
1989	0.998139977455139
1990	0.997680008411407
1991	0.998510003089905
1992	0.998700022697449
1993	0.996710002422333
1994	0.995180010795593
1995	0.998780012130737
1996	0.997839987277985
1997	1.00212001800537
1998	1.00778996944427
1999	1.00776994228363
2000	0.999599993228912
2001	1.00094997882843
2002	0.999970018863678
2003	1.00112998485565
2004	1.00215005874634
2005	1.00056004524231
2006	0.999010026454926
2007	0.998009979724884
2008	0.99712997674942
2009	0.998000025749207
2010	0.996940016746521
2011	0.995670020580292
2012	0.995980024337769
2013	0.997919976711273
2014	0.999840021133423
2015	1.00080001354218
2016	0.996159970760345
2017	0.994449973106384
2018	0.996909976005554
2019	0.996800005435944
2020	0.996389985084534