Year	gross (GPI)
1971	1.02515995502472
1972	1.02131998538971
1973	1.0105299949646
1974	1.00179994106293
1975	1.02717995643616
1976	1.11039996147156
1977	1.11572003364563
1978	1.09121000766754
1979	1.09748005867004
1980	1.1577399969101
1981	1.00445997714996
1982	1.07465994358063
1983	1.03365004062653
1984	1.03961002826691
1985	1.0248099565506
1989	1.06921994686127
1990	0.904760003089905
1999	1.05316996574402
2000	1.0378999710083
2001	1.00370001792908
2002	1.00069999694824
2003	1.0106999874115
2004	1.0042200088501
2005	0.989400029182434
2006	1.021360039711
2007	1.01164996623993
2008	1.0234500169754
2009	1.01517999172211
2010	1.00442004203796
2011	1.03733003139496
2014	1.02833998203278
2015	1.03568994998932
2016	1.04864001274109
2017	1.04184997081757
2018	1.03919994831085
2019	1.04303002357483
2020	1.03185999393463
2021	1.02567994594574