Year	gross (GPI)
1971	0.569379985332489
1972	0.568989992141724
1973	0.627229988574982
1974	0.587819993495941
1975	0.583050012588501
1976	0.569379985332489
1977	0.582449972629547
1978	0.576200008392334
1979	0.584429979324341
1980	0.578509986400604
1981	0.580619990825653
1982	0.593919992446899
1983	0.594519972801209
1984	0.59400999546051
1985	0.608319997787476
1986	0.610440015792847
1987	0.608489990234375
1988	0.60861998796463
1989	0.611519992351532
1990	0.602729976177216
1991	0.601999998092651
1992	0.60233998298645
1993	0.61914998292923
1994	0.639159977436066
1995	0.686710000038147
1996	0.668420016765594
1997	0.666790008544922
1998	0.704720020294189
1999	0.715480029582977
2000	0.745389997959137
2001	0.733349978923798
2002	0.75297999382019
2003	0.762650012969971
2004	0.775979995727539
2005	0.785449981689453
2006	0.805320024490356
2007	0.819069981575012
2008	0.833959996700287
2009	0.84485000371933
2010	0.857580006122589
2011	0.870090007781982
2012	0.874549984931946
2013	1.08888375759125
2014	0.887199997901917
2015	0.897539973258972
2016	0.882719993591309
2017	0.894479990005493
2018	0.901000022888184
2020	0.907537221908569