Year	gross (GPI)
1970	0.418469995260239
1971	0.418779999017715
1972	0.426750004291534
1973	0.43478998541832
1974	0.44352999329567
1975	0.45278999209404
1976	0.455280005931854
1977	0.456569999456406
1978	0.461620002985001
1979	0.468019992113113
1980	0.475890010595322
1981	0.482959985733032
1982	0.485599994659424
1983	0.534439980983734
1984	0.508239984512329
1985	0.516709983348846
1986	0.533370018005371
1987	0.539919972419739
1988	0.552640020847321
1989	0.565919995307922
1990	0.578019976615906
1991	0.595510005950928
1992	0.611859977245331
1993	0.629100024700165
1994	0.648169994354248
1995	0.65582001209259
1996	0.667859971523285
1997	0.692359983921051
1998	0.716600000858307
1999	0.739369988441467
2000	0.749939978122711
2001	0.761420011520386
2002	0.787419974803925
2003	0.83950001001358
2004	0.831399977207184
2005	0.849030017852783
2006	0.857209980487823
2007	0.875450015068054
2008	0.897109985351563
2009	0.925909996032715
2010	0.93283998966217
2011	0.945749998092651
2012	0.949949979782104
2013	0.990260004997253
2014	1.00039005279541
2015	1.00066995620728
2016	1.00373005867004
2017	1.00197994709015
2018	1.00426995754242
2019	1.00838994979858
2020	0.992219984531403