Year	gross (GPI)
1970	0.755370020866394
1971	0.755259990692139
1972	0.756250023841858
1973	0.755699992179871
1974	0.75424998998642
1975	0.790520012378693
1976	0.811010003089905
1977	0.817120015621185
1978	0.816460013389587
1979	0.817430019378662
1980	0.82029002904892
1981	0.821850001811981
1982	0.820580005645752
1983	0.818310022354126
1984	0.823989987373352
1985	0.829909980297089
1986	0.845300018787384
1987	0.852209985256195
1988	0.856339991092682
1989	0.858850002288818
1990	0.864700019359589
1991	0.874689996242523
1992	0.882049977779388
1993	0.888650000095367
1994	0.893119990825653
1995	0.895879983901978
1996	0.898679971694946
1997	0.904330015182495
1998	0.906620025634766
1999	0.911670029163361
2000	0.914240002632141
2001	0.91923999786377
2002	0.921280026435852
2003	0.944649994373322
2004	0.946370005607605
2005	0.949469983577728
2006	0.953499972820282
2007	0.95661997795105
2008	0.964309990406036
2009	0.969489991664886
2010	0.9721400141716
2011	0.97418999671936
2012	0.978879988193512
2013	0.997810006141663
2014	0.997659981250763
2015	0.999270021915436
2016	1.00847995281219
2017	1.00607001781464
2018	0.980260014533997
2019	0.98132997751236
2020	0.980660021305084