Year	gross (GPI)
1992	1.00940001010895
1993	0.992150008678436
1994	0.991710007190704
1995	0.99141001701355
1996	0.989539980888367
1997	0.988759994506836
1998	0.987550020217896
1999	0.988470017910004
2000	0.989650011062622
2001	0.990440011024475
2002	0.990480005741119
2003	0.992649972438812
2004	0.993560016155243
2005	0.995999991893768
2006	0.995469987392426
2007	0.994690001010895
2008	0.992959976196289
2009	0.993809998035431
2010	0.994319975376129
2011	0.993319988250732
2012	0.997370004653931
2013	0.994589984416962
2014	0.996529996395111
2015	0.998730003833771
2016	1.00025999546051
2017	1.00257003307343
2018	1.00722002983093
2019	1.00838994979858
2020	1.0077600479126