Year	gross (GPI)
1970	0.657689988613129
1971	0.649089992046356
1972	0.623179972171783
1973	0.608839988708496
1974	0.593500018119812
1975	0.576820015907288
1976	0.5590900182724
1977	0.563769996166229
1978	0.542840003967285
1979	0.532140016555786
1980	0.535610020160675
1981	0.535690009593964
1982	0.542060017585754
1983	0.540440022945404
1984	0.540549993515015
1985	0.548049986362457
1986	0.540719985961914
1987	0.54790997505188
1988	0.549560010433197
1989	0.55077999830246
1990	0.557609975337982
1991	0.553680002689362
1992	0.558589994907379
1993	0.559059977531433
1994	0.565739989280701
1995	0.570029973983765
1996	0.579720020294189
1997	0.589489996433258
1998	0.605809986591339
1999	0.620850026607513
2000	0.632719993591309
2001	0.631699979305267
2002	0.656960010528564
2003	0.643199980258942
2004	0.649980008602142
2005	0.653590023517609
2006	0.670040011405945
2007	0.665160000324249
2008	0.649850010871887
2009	0.652549982070923
2010	0.647310018539429
2011	0.646960020065308
2012	0.667739987373352
2013	0.664189994335175
2014	0.658659994602203
2015	0.668569982051849
2016	0.685429990291595
2017	0.69226998090744
2018	0.705739974975586
2019	0.721109986305237
2020	0.737600028514862
2021	0.741550028324127