Year	gross (GPI)
1970	0.583019971847534
1971	0.582210004329681
1972	0.59934002161026
1973	0.598039984703064
1974	0.597180008888245
1975	0.604269981384277
1976	0.611930012702942
1977	0.627099990844727
1978	0.635969996452332
1979	0.639320015907288
1980	0.651250004768372
1981	0.667800009250641
1982	0.689740002155304
1983	0.67765998840332
1984	0.699299991130829
1985	0.693029999732971
1986	0.703819990158081
1987	0.711019992828369
1988	0.726080000400543
1989	0.734260022640228
1990	0.742810010910034
1991	0.755100011825562
1992	0.762090027332306
1993	0.768530011177063
1994	0.774140000343323
1995	0.7776700258255
1996	0.782410025596619
1997	0.792779982089996
1998	0.801320016384125
1999	0.819850027561188
2000	0.831219971179962
2001	0.837960004806519
2002	0.844619989395142
2003	0.851419985294342
2004	0.843630015850067
2005	0.86531001329422
2006	0.874639987945557
2007	0.881120026111603
2008	0.891070008277893
2009	0.896539986133575
2010	0.908349990844727
2011	0.910430014133453
2012	0.916329979896545
2013	0.920650005340576
2014	0.926180005073547
2015	0.938210010528564
2016	0.938839972019196
2017	0.942330002784729
2018	0.941479980945587
2019	0.943490028381348
2020	0.947740018367767