Year	gross (GPI)
1971	0.396079987287521
1972	0.415950000286102
1973	0.436060011386871
1974	0.459989994764328
1976	0.533129990100861
1977	0.577189981937408
1978	0.601310014724731
1979	0.607749998569489
1980	0.644729971885681
1981	0.666339993476868
1982	0.64902001619339
1983	0.662540018558502
1984	0.685509979724884
1985	0.714619994163513
1986	0.735329985618591
1987	0.727789998054504
1988	0.771109998226166
1989	0.881789982318878
1994	0.912859976291656
1995	0.840939998626709
1996	0.906930029392242
1997	0.884899973869324
1999	0.879190027713776
2019	1.07875549793243