Year	gross (GPI)
1970	0.69252997636795
1971	0.694999992847443
1972	0.704150021076202
1973	0.709930002689362
1974	0.715430021286011
1975	0.719889998435974
1976	0.722119987010956
1977	0.739180028438568
1978	0.751259982585907
1979	0.761510014533997
1980	0.7744500041008
1981	0.784850001335144
1982	0.802100002765656
1983	0.800549983978271
1984	0.801169991493225
1985	0.802940011024475
1986	0.808610022068024
1987	0.821569979190826
1988	0.80077999830246
1989	0.822759985923767
1990	0.808570027351379
1991	0.819760024547577
1992	0.828930020332336
1993	0.822430014610291
1994	0.818750023841858
1995	0.811100006103516
1996	0.809539973735809
1997	0.80128002166748
1998	0.794309973716736
1999	0.801249980926514
2000	0.806270003318787
2001	0.813880026340485
2002	0.813099980354309
2003	0.818889975547791
2004	0.814909994602203
2005	0.837499976158142
2006	0.849059998989105
2007	0.858590006828308
2008	0.868499994277954
2009	0.878639996051788
2010	0.885439991950989
2011	0.893620014190674
2012	0.907079994678497
2013	0.91049998998642
2014	0.91346001625061
2015	0.918940007686615
2016	0.912569999694824
2017	0.914650022983551
2018	0.916530013084412
2019	0.914680004119873
2020	0.913860023021698