Year	gross (GPI)
1971	0.943239986896515
1972	0.944060027599335
1973	0.946680009365082
1974	0.956489980220795
1975	0.964129984378815
1976	0.961989998817444
1977	0.964900016784668
1978	0.965439975261688
1979	0.98308002948761
1980	0.97162002325058
1981	0.979680001735687
1983	0.99702000617981
1984	1.00261998176575
1985	0.995840013027191
1986	0.999509990215302
1987	1.00034999847412
1988	1.00278997421265
1993	0.99879002571106
1996	1.01156997680664
1998	1.01417994499207
1999	1.01150000095367
2000	1.00574994087219
2001	1.01030004024506
2002	1.0048600435257
2003	1.00785005092621
2004	1.00227999687195
2005	1.00459003448486
2006	1.00567996501923
2007	1.0066499710083
2009	1.02678000926971
2010	1.02145004272461
2011	1.02350997924805
2012	1.02807998657227
2013	1.02394998073578
2014	1.02267003059387
2015	1.02245998382568
2016	1.02094995975494
2017	1.01995003223419
2018	1.02191996574402
2019	1.02401995658875
2020	1.02296996116638