Year	gross (GPI)
1970	0.918730020523071
1971	0.914200007915497
1972	0.919889986515045
1973	0.915709972381592
1974	0.92153000831604
1975	0.926159977912903
1976	0.936969995498657
1977	0.927820026874542
1978	0.934239983558655
1979	0.939740002155304
1980	0.975099980831146
1983	0.976199984550476
1984	0.993019998073578
1988	1.01048004627228
1989	0.987209975719452
1991	1.0058000087738
1992	0.999639987945557
1993	0.994639992713928
1998	0.958069980144501
1999	0.948189973831177
2000	0.950020015239716
2001	0.958039999008179
2002	0.951219975948334
2003	0.966759979724884
2004	0.970359981060028
2005	0.972609996795654
2006	0.977020025253296
2007	1.00117003917694
2008	0.975920021533966
2009	0.972739994525909
2010	0.966199994087219
2011	0.962909996509552
2012	0.963469982147217
2013	0.970470011234283
2014	0.977069973945618