Year	gross (GPI)
1970	0.929880023002625
1971	0.932919979095459
1972	0.942910015583038
1973	0.939830005168915
1975	0.947239995002747
1976	0.946789979934692
1977	0.9480100274086
1978	0.951569974422455
1986	0.965040028095245
1987	0.967689990997314
1988	0.970030009746552
1989	0.98743999004364
1990	0.984740018844604
1991	0.990700006484985
1993	0.993359982967377
1994	0.992309987545013
1995	1.00116002559662
1996	0.999729990959167
1997	1.00182998180389
1998	0.998700022697449
1999	0.993839979171753
2000	0.993110001087189
2001	0.991020023822784
2002	0.989080011844635
2003	0.990320026874542
2004	0.994260013103485
2005	0.998319983482361
2006	1.00145995616913
2007	1.00171995162964
2008	1.00466001033783
2009	1.00653994083405
2010	1.00478994846344
2011	1.0083099603653
2012	1.01601004600525