Year	gross (GPI)
1971	0.961600005626678
1972	0.96806001663208
1973	0.974259972572327
1974	0.979860007762909
1975	0.963490009307861
1976	0.974629998207092
1977	0.979030013084412
1978	0.990010023117065
1979	0.998860001564026
1980	1.01188004016876
1981	1.01075994968414
1982	1.02261996269226
1983	1.02553999423981
1984	1.02098000049591
1985	1.01944005489349
1986	1.01412999629974
1987	1.01759004592896
1988	1.01156997680664
1989	1.00878000259399
1990	1.01095998287201
1991	1.01181995868683
1992	1.01303005218506
1993	1.00917994976044
1994	1.00581002235413
1995	1.00364005565643
1996	1.00730001926422
1997	1.01171004772186
1999	1.0129599571228
2000	1.0119800567627
2001	1.0058399438858
2002	1.01154005527496
2003	1.01032996177673
2004	1.01148998737335
2005	1.00908005237579
2006	1.00741994380951
2007	1.00611996650696
2008	1.00065004825592
2009	1.00186002254486
2010	1.00617003440857
2011	1.00434994697571
2012	1.00855004787445
2013	1.00329995155334
2014	1.00445997714996
2015	0.996190011501312
2016	0.994809985160828
2017	0.992799997329712
2018	0.983219981193542
2019	0.981190025806427
2020	0.981880009174347