Year	gross (GPI)
1992	0.982429981231689
1993	0.968859970569611
1994	0.972190022468567
1995	0.972899973392487
1996	0.974489986896515
1997	0.976909995079041
1998	0.976279973983765
1999	0.978969991207123
2000	0.982500016689301
2001	0.983269989490509
2002	0.982129991054535
2003	0.980069994926453
2004	0.980449974536896
2005	0.980390012264252
2006	0.978070020675659
2007	0.980080008506775
2008	0.978049993515015
2009	0.960330009460449
2010	0.961250007152557
2011	0.96000999212265
2012	0.96136999130249
2013	0.964460015296936
2014	0.965309977531433
2015	0.966109991073608
2016	0.963729977607727
2017	0.957650005817413
2018	0.960990011692047
2019	0.965369999408722
2020	0.970099985599518