Year	gross (GPI)
1971	0.402920007705688
1972	0.425249993801117
1973	0.442999988794327
1974	0.468239992856979
1975	0.464989989995956
1976	0.485159993171692
1977	0.51104998588562
1978	0.525470018386841
1979	0.539529979228973
1980	0.549860000610352
1981	0.549870014190674
1982	0.565710008144379
1983	0.570770025253296
1984	0.592149972915649
1985	0.614579975605011
1986	0.629199981689453
1987	0.646960020065308
1988	0.659340023994446
1989	0.674950003623962
1990	0.68502002954483
1991	0.71356999874115
1992	0.718020021915436
1995	0.68639999628067
1997	0.802940011024475
1998	0.72681999206543
1999	0.838680028915405
2001	0.810869991779327
2002	0.615400016307831
2003	0.835979998111725
2004	0.787819981575012
2005	0.78847998380661
2006	0.791339993476868
2007	0.774860024452209
2008	0.798780024051666
2009	0.833559989929199
2010	0.809720456600189
2011	0.844569981098175
2012	0.85496997833252
2013	0.854900002479553
2014	0.850319981575012
2015	0.855030000209808
2016	0.857959985733032
2017	0.86700826883316
2018	0.865007758140564
2019	0.865743100643158
2020	0.871883749961853
2021	1.0976597070694