Year	gross (GPI)
1971	1.00160002708435
1972	0.994809985160828
1973	1.0006400346756
1977	1.00097000598907
1982	1.00958001613617
1983	1.0252799987793
1984	1.01663994789124
1985	1.01724994182587
1987	1.01423001289368
1988	1.01215004920959
1989	1.01593995094299
1990	1.02665996551514
1991	1.01394999027252
1992	1.00916004180908
1993	1.01186001300812
2004	1.01081001758575