Year	gross (GPI)
1970	0.645399987697601
1971	0.649439990520477
1972	0.643610000610352
1973	0.641059994697571
1974	0.638629972934723
1975	0.624819993972778
1976	0.616249978542328
1977	0.612569987773895
1978	0.609040021896362
1979	0.60887998342514
1980	0.619549989700317
1981	0.627789974212646
1982	0.650449991226196
1983	0.656610012054443
1984	0.660229980945587
1985	0.663940012454987
1986	0.668299973011017
1987	0.667959988117218
1988	0.669529974460602
1989	0.671199977397919
1990	0.672259986400604
1991	0.669749975204468
1992	0.669730007648468
1993	0.665790021419525
1994	0.644420027732849
1995	0.675589978694916
1996	0.671389997005463
1997	0.666109979152679
1998	0.659739971160889
1999	0.656260013580322
2000	0.657959997653961
2001	0.65693998336792
2002	0.67044997215271
2003	0.685010015964508
2004	0.676810026168823
2005	0.689109981060028
2006	0.693419992923737
2007	0.705780029296875
2008	0.718089997768402
2009	0.731289982795715
2010	0.748189985752106
2011	0.767769992351532
2012	0.779779970645905
2013	0.789699971675873
2014	0.79067999124527
2015	0.806240022182465
2016	0.807929992675781
2017	0.815240025520325
2018	0.818560004234314
2019	0.814989984035492
2020	0.818710029125214