Year	gross (GPI)
1970	1.00850999355316
1971	1.0102299451828
1972	1.01499998569489
1973	1.01625001430511
1974	1.01405000686646
1975	1.02920997142792
1976	1.04072999954224
1977	1.02831995487213
1978	1.02953004837036
1979	1.02969002723694
1980	1.0388799905777
1981	1.03991997241974
1982	1.03287994861603
1983	1.03214001655579
1984	1.03071999549866
1985	1.03146004676819
1986	1.03656995296478
1987	1.021360039711
1988	1.02566003799438
1989	1.03052997589111
1990	1.02845001220703
1991	1.02092003822327
1992	1.01487994194031
1993	1.01013994216919
1994	1.01279997825623
1995	1.0129200220108
1996	1.01749002933502
1997	1.01807999610901
1998	1.01227998733521
1999	1.01144003868103
2000	1.01122999191284
2001	1.00938999652863
2002	1.02090001106262
2003	1.01905000209808
2004	1.01774001121521
2005	1.02058005332947
2006	1.02260994911194
2007	1.0222100019455
2008	1.02030003070831
2009	1.01089000701904
2010	1.02293002605438
2011	1.0254100561142
2012	1.02786004543304
2013	1.01979994773865
2014	1.02239000797272
2015	1.03471004962921
2016	1.0179500579834
2017	1.01927995681763
2018	1.01075994968414
2019	1.01321995258331
2020	1.01545000076294