Year	gross (GPI)
1971	1.02046000957489
1972	1.01899003982544
1973	1.01665997505188
1974	1.01572000980377
1975	1.02927994728088
1976	0.992349982261658
1977	1.02862000465393
1978	1.02751004695892
1979	1.03314995765686
1980	1.00325000286102
1981	1.0024299621582
1982	1.00214004516602
1983	1.00312995910645
1984	0.999270021915436
1985	1.00494003295898
1986	0.998910009860992
1987	1.00252997875214
1988	1.00346994400024
1989	1.00299000740051
1990	1.00312995910645
1991	1.00124001502991
1992	0.998109996318817
1993	0.997420012950897
1994	0.997820019721985
1995	1.00337994098663
1996	0.996200025081635
1998	1.00311005115509
1999	1.00346994400024
2000	1.00285995006561
2001	1.00310003757477
2002	1.00270998477936
2004	0.998690009117126
2005	0.99888002872467
2006	1.00048995018005
2007	1.00071001052856
2008	1.0056300163269
2009	1.00366997718811
2010	1.00204002857208
2011	0.994090020656586
2012	0.991110026836395
2013	0.989679992198944
2014	0.988600015640259
2015	0.986710011959076
2016	0.988309979438782
2017	0.993589997291565
2018	0.998889982700348
2019	0.998369991779327
2020	0.999549984931946