Year	gross (GPI)
1970	1.05122995376587
1971	1.05627000331879
1972	1.06000995635986
1973	1.08221995830536
1974	1.09349000453949
1975	1.12218999862671
1976	1.06649994850159
1977	1.07942998409271
1978	1.06562995910645
1979	1.03605997562408
1980	1.0244300365448
1981	1.00713002681732
1982	1.00897002220154
1983	1.019700050354
1984	1.03717005252838
1985	1.03592002391815
1986	1.02084004878998
1987	1.03717005252838
1988	1.03296005725861
1989	0.999170005321503
1991	1.00049996376038
1992	0.987959980964661
1993	0.985830008983612
1994	1.01138997077942
1995	1.01523995399475
1996	1.02499997615814
1997	1.01372003555298
1998	1.02102994918823
1999	1.02688002586365
2000	1.028480052948
2001	1.01065003871918
2002	0.997290015220642
2003	0.985329985618591
2004	0.991609990596771
2005	0.981060028076172
2006	0.996840000152588
2007	1.02145004272461
2008	1.03262996673584
2009	1.02830004692078
2010	1.03083002567291
2011	1.05209004878998
2012	1.03964996337891
2013	1.02155995368958
2014	1.01517999172211
2015	1.03042995929718
2016	1.03249001502991
2017	1.05167996883392
2018	1.05868005752563
2019	1.04867005348206
2020	1.04321002960205
2021	1.03125