Year	gross (GPI)
1970	1.00287997722626
1971	0.990100026130676
1972	0.997370004653931
1973	0.998660027980804
1974	1.00898003578186
1975	0.975969970226288
1976	0.997420012950897
1977	1.00179004669189
1978	0.995630025863647
1979	0.998870015144348
1980	0.998250007629395
1981	0.988719999790192
1982	0.989319980144501
1983	0.999939978122711
1984	1.00350999832153
1985	1.00309002399445
1986	1.02039003372192
1988	1.00250005722046
1990	1.0076299905777
1991	1.01215994358063
1992	1.01003003120422
1993	1.0063099861145
1994	1.00634002685547
1995	1.00718998908997
1996	1.02178001403809
1997	1.01945996284485
1998	1.0426299571991
1999	1.0181599855423
2000	1.01557004451752
2003	0.990859985351563
2004	0.995540022850037
2005	0.999199986457825
2006	0.998139977455139
2007	1.00218999385834
2008	0.999610006809235
2009	0.999469995498657
2010	1.00049996376038
2011	0.998040020465851
2012	0.996270000934601