Year	gross (GPI)
1970	0.994379997253418
1971	0.994140028953552
1972	0.995419979095459
1973	1.00460994243622
1974	0.994199991226196
1975	0.995599985122681
1976	1.00577998161316
1977	0.995000004768372
1978	0.995379984378815
1979	0.993489980697632
1980	0.995000004768372
1981	0.995100021362305
1982	0.995450019836426
1983	0.995350003242493
1984	0.993749976158142
1985	0.992669999599457
1986	0.991739988327026
1987	0.993579983711243
1988	0.990769982337952
1989	0.993260025978088
1990	0.99466997385025
1991	0.996490001678467
1992	0.996990025043488
1993	0.995500028133392
1994	0.993789970874786
1995	0.990499973297119
1996	0.989929974079132
1997	0.99031001329422
1998	0.989530026912689
1999	0.99032998085022
2000	0.99194997549057
2001	0.992500007152557
2002	0.990760028362274
2003	0.991490006446838
2004	0.99151998758316
2005	0.990450024604797
2006	0.991100013256073
2007	0.991699993610382
2008	0.989989995956421
2009	0.991389989852905
2010	0.991620004177094
2011	0.993560016155243
2012	0.995760023593903
2013	0.998369991779327
2014	0.998589992523193
2015	0.999029994010925
2016	0.999779999256134
2017	0.996619999408722
2018	0.996240019798279
2019	0.998650014400482
2020	0.999610006809235