Year	gross (GPI)
1971	1.03027999401093
1972	1.02989995479584
1973	1.02983999252319
1974	1.03006994724274
1975	1.03024005889893
1976	1.0306099653244
1977	1.03042995929718
1978	1.03061997890472
1979	1.03155994415283
1982	1.04683005809784
1983	1.04663002490997
1984	1.02847003936768
1985	1.02763998508453
1986	1.02705001831055
1987	1.10223996639252
1988	1.1045800447464
1989	0.965160012245178
1990	0.941680014133453
1991	0.981480002403259
1992	1.07976996898651
1993	1.05032002925873
1994	1.00961995124817
1995	1.02107000350952
1996	1.0215699672699
1997	1.02149999141693
1998	1.0283499956131
1999	1.02321994304657
2000	1.01072001457214
2001	1.01726996898651
2002	1.01429998874664
2003	1.01259994506836
2004	1.00547003746033
2005	1.00723004341125
2006	1.00880002975464
2007	1.00705003738403
2008	1.00634002685547
2009	1.00645995140076
2010	1.00234997272491
2011	0.999260008335114
2012	1.00086998939514
2013	1.00463998317719
2014	1.00285995006561
2015	1.00706005096436
2016	1.00721001625061
2017	1.00648999214172
2018	1.00498998165131
2019	1.00761997699738
2020	1.00697004795074