Year	gross (GPI)
1970	0.987259984016418
1971	0.989700019359589
1972	0.988399982452393
1973	0.985199987888336
1974	0.997089982032776
1975	0.992860019207001
1976	0.99848997592926
1977	1.00171005725861
1978	1.0042599439621
1979	1.00639998912811
1980	1.01209998130798
1981	1.01267004013062
1982	1.01304996013641
1983	1.01084005832672
1984	1.00631999969482
1985	1.0066499710083
1986	1.01004004478455
1987	1.00557994842529
1988	1.00815999507904
1989	1.00783002376556
1990	1.00038003921509
1999	1.00671994686127
2000	1.00347995758057
2001	1.00603997707367
2002	1.00331997871399
2004	1.00558996200562
2005	1.00334000587463
2006	1.00815999507904
2007	1.0045599937439
2008	1.00504994392395
2009	1.0064400434494
2010	1.0006799697876
2011	1.00975000858307
2013	1.00918996334076
2014	1.01640999317169
2015	1.00832998752594
2016	1.00378000736237
2017	1.01170003414154
2021	1.01088798046112