Year	gross (GPI)
1971	0.90337997674942
1972	0.910470008850098
1973	0.93001002073288
1974	0.937030017375946
1975	0.943239986896515
1976	0.952899992465973
1977	0.955780029296875
1978	0.955720007419586
1979	0.962719976902008
1980	0.973339974880219
1981	0.970960021018982
1982	0.975920021533966
1983	0.978219985961914
1984	0.981429994106293
1985	0.985099971294403
1986	0.980820000171661
1987	0.998839974403381
1988	0.989960014820099
1989	0.999180018901825
1992	0.998369991779327
1994	0.997919976711273
1995	0.997250020503998
1996	1.00177001953125
1997	0.999019980430603
1999	1.00460004806519
2001	1.00111997127533
2002	0.995369970798492
2003	0.994419991970062
2011	0.968609988689423
2019	0.967231214046478