Year	gross (GPI)
1971	0.992169976234436
1972	1.00375998020172
1973	1.00575995445251
1974	0.905780017375946
1975	0.967060029506683
1976	1.05288004875183
1977	1.04622995853424
1978	1.03207004070282
1979	1.03290998935699
1980	1.06754994392395
1981	1.00108003616333
1982	1.01780998706818
1983	0.984560012817383
1984	1.01726996898651
1985	0.990369975566864
1989	1.03477001190186
1990	0.951020002365112
1999	1.01550996303558
2000	1.0069500207901
2001	0.99533998966217
2002	0.995400011539459
2003	0.994340002536774
2004	0.992079973220825
2005	0.993229985237122
2006	1.00021994113922
2007	1.00935995578766
2008	1.01191997528076
2009	1.0108699798584
2010	1.01068997383118
2011	1.01800000667572
2014	1.01625001430511
2015	1.01370000839233
2016	1.0222100019455
2017	1.00207996368408
2018	0.999639987945557
2019	0.998679995536804
2020	1.00007998943329
2021	0.99848997592926