Year	gross (GPI)
1973	1.03131997585297
1974	1.02836000919342
1975	1.06938004493713
1976	1.07161998748779
1977	1.05190002918243
1979	1.05279004573822
1980	1.0702600479126
1981	1.06610000133514
1983	1.05406999588013
1984	1.05046999454498
1985	1.04796004295349
1986	1.0618599653244
1987	1.02137005329132
1988	1.03334999084473
1989	1.04735994338989
1991	1.03446996212006
1993	1.00894999504089
1999	1.00741994380951
2000	1.0090399980545
2001	1.00501000881195
2002	1.01263999938965
2003	1.01672005653381
2004	1.02067005634308
2005	1.02327001094818
2007	1.03213000297546