Year	gross (GPI)
1971	0.338869988918304
1972	0.347680002450943
1973	0.369150012731552
1974	0.383240014314651
1975	0.396230012178421
1976	0.361589998006821
1977	0.350479990243912
1978	0.331950008869171
1979	0.324079990386963
1980	0.314839988946915
1982	0.360379993915558
1983	0.371239989995956
1984	0.416689991950989
1985	0.485850006341934
1986	0.457469999790192
1987	0.45194000005722
1988	0.451730012893677
1989	0.463869988918304
1990	0.482560008764267
1991	0.49957001209259
1992	0.512470006942749
1993	0.572529971599579
1994	0.56511002779007
1995	0.586189985275269
1996	0.595510005950928
1997	0.654560029506683
1998	0.58270001411438
1999	0.593729972839355
2000	0.586399972438812
2001	0.599039971828461
2002	0.612240016460419
2003	0.620729982852936
2004	0.634079992771149
2005	0.645190000534058
2006	0.663110017776489
2007	0.682439982891083
2008	0.70169997215271
2009	0.713940024375916
2010	0.732500016689301
2011	0.745710015296936
2012	0.756519973278046
2013	0.765600025653839
2014	0.773000001907349
2015	0.78329998254776
2016	0.790759980678558
2017	0.797789990901947
2018	0.810829997062683
2019	0.82438999414444
2020	0.832859992980957
2021	0.845170021057129
2022	0.860520005226135