Year	gross (GPI)
1971	1.00824999809265
1972	1.00718998908997
1973	1.0068199634552
1974	1.00703001022339
1975	1.00756001472473
1976	1.00814998149872
1977	1.00805997848511
1978	1.00820004940033
1979	1.00847005844116
1981	1.00907003879547
1982	1.00916004180908
1983	1.00929999351501
1984	0.969900012016296
1985	0.970080018043518
1986	0.970130026340485
1987	0.970359981060028
1988	0.970340013504028
1989	1.00484001636505
1990	1.00349998474121
1991	1.00603997707367
1992	1.16701996326447
1993	1.01095998287201
1994	1.00281000137329
1995	0.998969972133636
1996	0.992150008678436
1997	0.999620020389557
1998	0.998120009899139
1999	0.993179976940155
2000	0.995630025863647
2001	0.990970015525818
2002	0.987299978733063
2003	0.984189987182617
2004	0.986199975013733
2005	0.985809981822968
2006	0.992070019245148
2007	0.992519974708557
2008	0.99278998374939
2009	0.99550998210907
2010	0.995999991893768
2011	0.994490027427673
2012	0.999080002307892
2013	1.00066995620728
2014	1.0001699924469
2015	1.0035799741745
2016	1.00551998615265
2017	1.00559997558594
2018	1.00601994991302
2019	1.00461995601654
2020	1.00294995307922