Year	gross (GPI)
1971	0.0951199978590012
1972	0.123510003089905
1973	0.14606000483036
1974	0.165920004248619
1975	0.192560002207756
1976	0.28931000828743
1977	0.331299990415573
1978	0.327630013227463
1979	0.387970000505447
1980	0.436890006065369
1981	0.524869978427887
1982	0.585510015487671
1983	0.656759977340698
1984	0.771809995174408
1985	0.833249986171722
1986	0.924449980258942
1987	0.936410009860992
1991	1.0200799703598
1992	0.860010027885437
1993	1.08436000347137
1994	1.05971002578735
1995	1.16298997402191
1996	1.20931005477905
1997	1.17225003242493
1998	1.34605002403259
1999	1.4021999835968
2000	1.42421996593475
2001	1.37715995311737
2002	1.3712899684906
2003	1.40190994739532
2004	1.38779997825623
2005	1.34595000743866
2006	1.3568400144577
2007	1.27941000461578
2008	1.28534996509552
2009	1.28743994235992
2011	1.45516002178192
2012	1.38405001163483
2013	1.3183399438858
2014	1.29963004589081
2015	1.26646995544434
2016	1.21495997905731
2017	1.14304995536804
2018	1.12967002391815
2019	1.11390995979309
2020	1.14408004283905
2021	1.05569005012512
2022	1.11363995075226