Year	gross (GPI)
1971	0.230839997529984
1972	0.225439995527267
1973	0.232960000634193
1974	0.244810000061989
1976	0.307980000972748
1977	0.288580000400543
1978	0.310380011796951
1979	0.320030003786087
1980	0.358999997377396
1981	0.501659989356995
1982	0.519850015640259
1983	0.532389998435974
1984	0.56129002571106
1985	0.553600013256073
1986	0.54737001657486
2007	0.460770010948181