Year	gross (GPI)
1971	0.427329987287521
1972	0.423390001058578
1973	0.435999989509583
1974	0.453280001878738
1975	0.503080010414124
1976	0.525330007076263
1977	0.57914000749588
1978	0.629180014133453
1979	0.798460006713867
1980	0.864910006523132
1981	0.911660015583038
1982	0.935909986495972
1983	0.915390014648438
1984	0.887920022010803
1985	0.859220027923584
1986	0.855379998683929
1987	0.849849998950958
1988	0.86735999584198
1989	0.833980023860931
1991	0.845250010490417
1992	0.858919978141785
1993	0.852219998836517
1996	0.857360005378723
1999	0.829089999198914
2000	0.830709993839264
2003	0.849200010299683
2004	0.843129992485046
2007	0.841690003871918