Year	gross (GPI)
1970	0.901619970798492
1971	0.901579976081848
1972	0.90090000629425
1973	0.915340006351471
1974	0.923829972743988
1975	0.93629002571106
1976	0.948729991912842
1977	0.963490009307861
1978	0.976880013942719
1979	0.980189979076386
1980	0.985780000686646
1981	0.992179989814758
1982	0.98905998468399
1983	0.987689971923828
1984	0.986679971218109
1985	0.986869990825653
1986	0.989409983158112
1987	0.988089978694916
1988	0.985859990119934
1989	0.984830021858215
1990	0.988139986991882
1991	0.987959980964661
1992	0.98785001039505
1993	0.985499978065491
1994	0.983650028705597
1995	0.986190021038055
1996	0.984319984912872
1997	0.988870024681091
1998	0.993960022926331
1999	0.995090007781982
2000	0.990180015563965
2001	0.990800023078918
2002	0.990369975566864
2003	0.992460012435913
2004	0.995019972324371
2005	0.995689988136292
2006	0.995899975299835
2007	0.996919989585876
2008	0.998420000076294
2009	1.00152003765106
2010	1.00023996829987
2011	0.998709976673126
2012	0.99888002872467
2013	1.00091004371643
2014	1.00277996063232
2015	1.00327003002167
2016	1.0022599697113
2017	0.999430000782013
2018	1.00273001194
2019	1.00277996063232
2020	1.00249004364014