Year	gross (GPI)
1971	0.555859982967377
1972	0.572200000286102
1973	0.577880024909973
1974	0.589359998703003
1975	0.630689978599548
1976	0.60343998670578
1977	0.581229984760284
1978	0.547249972820282
1979	0.480399996042252
1980	0.662670016288757
1981	0.753750026226044
1982	0.678189992904663
1983	0.843270003795624
1984	0.598879992961884
1985	0.614740014076233
1986	0.627990007400513
1987	0.673399984836578
1989	0.618690013885498
1991	0.793839991092682
1992	0.695500016212463
1993	0.717989981174469
1999	1.28004002571106
2000	1.33368003368378
2001	1.35196995735168
2002	1.33788001537323
2003	1.37931001186371
2004	1.21639001369476