Year	gross (GPI)
1971	0.977810025215149
1972	0.973749995231628
1973	0.979879975318909
1974	0.981230020523071
1975	0.99397999048233
1976	0.995970010757446
1977	1.01470994949341
1978	1.02075004577637
1979	1.02075004577637
1980	1.03001999855042
1981	1.03559005260468
1982	1.02956998348236
1983	1.03975999355316
1984	1.02453994750977
1985	1.02613997459412
1986	1.01534998416901
1987	1.0127899646759
1988	1.01037001609802
1989	1.01140999794006
1990	1.01566994190216
1991	1.0152200460434
1992	1.01418995857239
1993	1.06673002243042
1994	1.06898999214172
1995	1.08262002468109
1996	1.07925999164581
1999	1.08024001121521
2000	1.10614001750946
2001	1.11468005180359
2002	1.12233996391296
2003	1.10328996181488
2004	1.09829998016357
2005	1.11912000179291
2006	1.12715995311737
2007	1.13343000411987
2008	1.14632999897003
2009	1.15046000480652
2010	1.13919997215271
2011	1.13699996471405
2012	1.13976001739502
2013	1.13604998588562
2014	1.13396000862122
2015	1.13689994812012
2016	1.11991000175476
2017	1.12066996097565
2018	1.12371003627777
2019	1.12826001644135
2020	1.13031005859375