Year	gross (GPI)
1971	0.604870021343231
1972	0.60206001996994
1973	0.606100022792816
1974	0.607469975948334
1975	0.617389976978302
1976	0.638840019702911
1977	0.649730026721954
1978	0.661979973316193
1979	0.679639995098114
1980	0.689339995384216
1981	0.707210004329681
1982	0.727729976177216
1983	0.741850018501282
1984	0.762380003929138
1985	0.780460000038147
1986	0.793240010738373
1987	0.803780019283295
1988	0.812560021877289
1989	0.828890025615692
1990	0.843770027160645
1991	0.859769999980927
1992	0.876640021800995
1993	0.891629993915558
1994	0.9098100066185
1995	0.922290027141571
1996	0.936299979686737
1997	0.947269976139069
1999	0.97487998008728
2000	0.99523001909256
2001	1.00093996524811
2002	1.00112998485565
2003	1.02230000495911
2005	1.04344999790192
2006	1.04712998867035
2008	1.04604005813599
2009	1.04849004745483
2010	1.04806005954742
2011	1.03831994533539
2016	1.06780004501343