Year	gross (GPI)
1970	0.762939989566803
1971	0.762889981269836
1972	0.76323002576828
1973	0.762179970741272
1974	0.760129988193512
1975	0.798290014266968
1976	0.820039987564087
1977	0.825969994068146
1978	0.824790000915527
1979	0.825800001621246
1980	0.828390002250671
1981	0.829620003700256
1982	0.826340019702911
1983	0.823920011520386
1984	0.829659998416901
1985	0.8367999792099
1986	0.852930009365082
1987	0.859229981899261
1988	0.864820003509521
1989	0.867150008678436
1990	0.873329997062683
1991	0.883629977703094
1992	0.891560018062592
1993	0.898570001125336
1994	0.903490006923676
1995	0.908259987831116
1996	0.912180006504059
1997	0.918730020523071
1998	0.921519994735718
1999	0.925119996070862
2000	0.927510023117065
2001	0.933279991149902
2002	0.936259984970093
2003	0.962080001831055
2004	0.964829981327057
2005	0.964770019054413
2006	0.967660009860992
2007	0.970979988574982
2008	0.978569984436035
2009	0.982980012893677
2010	0.98514997959137
2011	0.987249970436096
2012	0.992049992084503
2013	1.01401996612549
2014	1.01396000385284
2015	1.01426994800568
2016	1.02508997917175
2017	1.02266001701355
2018	0.992669999599457
2019	0.993430018424988
2020	0.992009997367859