Year	gross (GPI)
1971	0.722100019454956
1972	0.730419993400574
1973	0.738059997558594
1974	0.74074000120163
1975	0.752420008182526
1976	0.768090009689331
1977	0.79067999124527
1978	0.81098997592926
1979	0.839550018310547
1980	0.859769999980927
1981	0.888310015201569
1982	0.875549972057343
1983	0.944769978523254
1984	0.957819998264313
1985	0.997810006141663
1986	1.01406002044678
1987	1.02292001247406
1988	1.01842999458313
1989	1.01313996315002
1990	1.03289997577667
1991	1.01270997524261
1992	1.01233994960785
1993	1.01986002922058
1994	1.02147996425629
1995	1.01041996479034
1996	0.995109975337982
1997	0.982630014419556
1998	0.988470017910004
1999	0.992269992828369
2000	1.01558005809784
2001	1.03849995136261
2002	1.02418994903564
2003	1.03138995170593
2004	1.03623998165131
2005	1.03588998317719
2006	1.05136001110077
2011	1.01778995990753
2012	1.00891995429993
2013	1.01669001579285
2014	1.01229000091553
2015	1.00990998744965
2016	1.02083003520966
2017	0.995800018310547
2018	0.98786997795105
2019	0.994170010089874