Year	gross (GPI)
1981	0.988349974155426
1986	0.999430000782013
1991	1.00750005245209
1992	1.00740003585815
1993	1.00584995746613
1994	0.936389982700348
1995	0.987020015716553
1996	1.01347005367279
1997	0.997810006141663
1998	1.01917004585266
1999	1.0270299911499
2000	1.03469002246857
2001	1.07604002952576
2002	1.08554995059967
2003	1.05939996242523
2004	1.032870054245
2005	1.04107999801636
2006	1.07231998443604
2007	1.00957000255585
2008	1.00952994823456
2009	1.00811004638672
2010	1.01420998573303
2011	1.01077997684479
2012	0.991330027580261
2013	0.98988002538681
2014	0.990939974784851
2015	1.00150001049042
2016	1.00329995155334
2017	1.01081001758575
2018	1.01153004169464
2019	1.00773000717163
2020	1.00504004955292
2021	1.00732004642487