Year	gross (GPI)
1970	0.945219993591309
1971	0.965659976005554
1972	0.97842001914978
1973	0.97996997833252
1974	0.994329988956451
1975	1.03825998306274
1976	1.03992998600006
1977	1.01477003097534
1978	1.02191996574402
1979	1.04095995426178
1980	1.03859996795654
1981	1.04803001880646
1982	1.04525995254517
1983	1.04848003387451
1984	1.04471004009247
1985	1.02506005764008
1986	1.04691994190216
1987	1.04699003696442
1988	1.04975998401642
1989	1.05397999286652
1990	1.0621600151062
1991	1.06949996948242
1992	1.06610000133514
1993	1.06798994541168
1994	1.06822001934052
1995	1.06900000572205
1996	1.06086003780365
1997	1.06379997730255
1998	1.06507003307343
1999	1.05994999408722
2000	1.06524002552032
2001	1.06049001216888
2002	1.05961000919342
2003	1.07569003105164
2004	1.07175004482269
2005	1.07343995571136
2006	1.07486999034882
2007	1.08941996097565
2008	1.09386003017426
2009	1.09055995941162
2010	1.08178997039795
2011	1.07863998413086
2012	1.06786000728607
2013	1.05901002883911
2014	1.0584100484848
2015	1.05491995811462
2016	1.04860997200012
2017	1.04270994663239
2018	1.04472005367279
2019	1.0489000082016
2020	1.05169999599457