Year	gross (GPI)
1970	0.963500022888184
1971	0.961510002613068
1972	0.960150003433228
1973	0.971010029315948
1974	0.97733998298645
1975	0.999490022659302
1976	1.00595998764038
1977	0.996949970722198
1978	0.997720003128052
1979	0.999440014362335
1980	1.01224994659424
1981	1.00525999069214
1982	1.00004005432129
1983	0.994899988174438
1984	0.988210022449493
1985	0.994490027427673
1986	1.00335001945496
1987	0.99822998046875
1988	1.00261998176575
1989	1.01138997077942
1990	1.0111700296402
1991	1.00969004631042
1992	1.01402997970581
1993	1.01245999336243
1994	1.01740002632141
1995	1.01113998889923
1996	1.01689004898071
1997	1.01445996761322
1998	1.01148998737335
1999	1.00301003456116
2000	1.00505995750427
2001	1.00069999694824
2002	1.0064799785614
2003	1.00277996063232
2004	0.994000017642975
2005	0.99864000082016
2006	1.01003003120422
2007	1.01417994499207
2008	1.02216005325317
2009	1.02169001102448
2010	1.02525997161865
2011	1.0234899520874
2012	1.03865003585815
2013	1.04300999641418
2014	1.04427003860474
2015	1.04021000862122
2016	1.03936004638672
2017	1.04868996143341
2018	1.04917001724243
2019	1.04546999931335
2020	1.0436999797821