Year	gross (GPI)
1970	1.04105997085571
1971	1.05069994926453
1972	1.05446004867554
1973	1.05460000038147
1975	1.07453000545502
1976	1.06679999828339
1977	1.07212996482849
1978	1.10195004940033
1979	1.07158994674683
1980	1.06571996212006
1982	1.06014001369476
1983	1.06175994873047
1984	1.0541900396347
1985	1.11160004138947
1986	1.10075998306274
1987	1.10325002670288
1988	1.11484003067017
1989	1.10672998428345
1990	1.07632994651794
1991	1.06664001941681
1992	1.05506002902985
1993	1.04834997653961
1994	1.03856003284454
1995	1.0440000295639
1996	1.04135000705719
1997	1.03982996940613
1998	1.03847002983093
1999	1.01891005039215
2000	1.02270996570587
2001	1.01872003078461
2002	1.00169003009796
2003	0.994939982891083
2004	0.990480005741119
2005	0.985570013523102
2006	0.986810028553009
2007	0.991119980812073
2008	0.989579975605011
2010	0.991659998893738
2011	0.988334059715271
2012	0.98236209154129
2013	0.984010994434357
2014	0.935280561447144
2015	0.99947065114975
2016	0.996287822723389
2017	0.991142213344574
2018	0.991461873054504
2019	0.993929445743561
2020	0.993812501430511