Year	gross (GPI)
1971	0.331510007381439
1972	0.339320003986359
1974	0.376489996910095
1984	0.563380002975464
1991	0.77512001991272
1992	0.84495997428894
1993	0.875890016555786
1994	0.843720018863678
1995	0.794990003108978
1996	0.756079971790314
1999	0.679570019245148
2000	0.672599971294403
2001	0.665929973125458
2002	0.627160012722015
2003	0.578130006790161
2004	0.577170014381409
2005	0.601589977741241
2006	0.633910000324249
2007	0.675270020961761
2008	0.731700003147125
2009	0.782589972019196
2010	0.830990016460419
2011	0.88332998752594
2012	0.904600024223328
2013	0.935770511627197
2014	0.94667375087738
2015	0.961709976196289