Year	gross (GPI)
1971	0.287299990653992
1972	0.327259987592697
1973	0.308290004730225
1974	0.310189992189407
1975	0.300929993391037
1976	0.310900002717972
1977	0.294860005378723
1978	0.298249989748001
1979	0.310909986495972
1980	0.316689997911453
1982	0.337020009756088
1983	0.33092001080513
1984	0.32328000664711
1985	0.31343999505043
1986	0.307810008525848
1987	0.305200010538101
1988	0.323000013828278
1989	0.310119986534119
1990	0.338750004768372
1991	0.33517000079155
1992	0.323780000209808
1994	0.338220000267029
1995	0.348800003528595
1996	0.348969995975494
1997	0.360249996185303
1999	0.398259997367859
2000	0.445060014724731
2001	0.457139998674393
2002	0.476110011339188
2003	0.491380006074905
2004	0.514370024204254
2005	0.530260026454926
2006	0.545520007610321
2007	0.528900027275085
2017	0.727500021457672
2021	0.81344997882843