Year	gross (GPI)
1971	1.02409994602203
1972	1.0905499458313
1973	0.958140015602112
1974	0.964339971542358
1975	0.938399970531464
1976	0.948539972305298
1977	0.950460016727448
1978	0.965780019760132
1979	0.960929989814758
1980	0.956730008125305
1981	0.962390005588531
1982	0.969659984111786
1983	0.983370006084442
1984	1.02118003368378
1985	1.01284003257751
1995	0.99481999874115
1997	0.997399985790253
2001	1.01419997215271
2002	1.04147005081177
2003	1.03671002388
2004	1.06508004665375
2005	1.05171000957489
2006	1.0789999961853
2011	0.983860015869141
2012	0.967710018157959
2013	0.972060024738312
2014	0.969969987869263
2015	0.981760025024414