Year	gross (GPI)
1971	0.534210026264191
1972	0.595089972019196
1973	0.663020014762878
1974	0.722769975662231
1975	0.75721001625061
1976	0.781729996204376
1977	0.81088000535965
1978	0.832669973373413
1979	0.844449996948242
1980	0.850589990615845
1981	0.853089988231659
1983	0.867420017719269
1986	0.91390997171402
2002	1.03412997722626
2003	1.01807999610901
2005	1.08396995067596
2006	1.05914998054504