Year	gross (GPI)
1970	0.705730020999908
1971	0.706969976425171
1972	0.712090015411377
1973	0.712779998779297
1974	0.710460007190704
1975	0.718670010566711
1976	0.727500021457672
1977	0.735790014266968
1978	0.738399982452393
1979	0.748889982700348
1980	0.754140019416809
1981	0.762769997119904
1982	0.768509984016418
1983	0.771089971065521
1984	0.779730021953583
1985	0.791209995746613
1986	0.800890028476715
1987	0.808589994907379
1988	0.81427001953125
1989	0.815900027751923
1990	0.820969998836517
1991	0.837279975414276
1992	0.846669971942902
1993	0.858950018882751
1994	0.86532998085022
1995	0.867380023002625
1996	0.870220005512238
1997	0.879109978675842
1998	0.880720019340515
1999	0.885410010814667
2000	0.890309989452362
2001	0.898209989070892
2002	0.904879987239838
2003	0.948480010032654
2004	0.95058000087738
2005	0.95278000831604
2006	0.958459973335266
2007	0.964789986610413
2008	0.978760004043579
2009	0.985010027885437
2010	0.990059971809387
2011	0.992590010166168
2012	0.99795001745224
2013	1.02918004989624
2014	1.02695000171661
2015	1.02819001674652
2016	1.04190003871918
2017	1.03720998764038
2018	0.991349995136261
2019	0.992680013179779
2020	0.991900026798248