Year	gross (GPI)
1973	0.268480002880096
1974	0.240050002932549
1975	0.277929991483688
1976	0.205050006508827
1977	0.252119988203049
1978	0.230330005288124
1979	0.261689990758896
1980	0.302159994840622
1981	0.332720011472702
1982	0.384660005569458
1983	0.379260003566742
1984	0.418599992990494
1985	0.464469999074936
1986	0.513469994068146
1987	0.564209997653961
1988	0.615610003471375
1989	0.672680020332336
1990	0.717899978160858
1991	0.806850016117096
1992	0.867850005626678
1993	0.911440014839172
1994	0.933390021324158
1995	0.946189999580383
1996	0.941349983215332
1997	0.989570021629334
1998	1.001620054245
1999	1.00875997543335
2000	0.992240011692047
2001	0.984610021114349
2002	0.9689000248909
2003	0.954079985618591
2005	0.963789999485016
2006	0.982110023498535
2007	0.988650023937225
2008	0.97843998670578
2009	0.949400007724762
2011	0.960189998149872
2012	0.988030016422272
2013	1.02034997940063
2015	0.98309999704361
2016	0.937319993972778
2017	0.940880000591278
2018	0.923309981822968
2019	0.914709985256195
2020	0.91881000995636
2021	0.936540007591248