Year	gross (GPI)
1981	0.975120007991791
1986	0.980359971523285
1989	0.963039994239807
1990	1.00525999069214
1991	1.03474998474121
1992	1.03519999980927
1999	1.02822005748749
2000	1.03480005264282
2001	1.00617003440857
2002	1.00756001472473
2003	1.01155996322632
2004	1.00874996185303
2005	1.00347995758057
2006	1.00310003757477
2007	1.00206995010376
2009	1.05002999305725
2010	0.996730029582977
2011	1.00397002696991
2012	0.998889982700348
2013	1.00828003883362
2014	1.00720000267029
2015	1.01370000839233
2016	0.998549997806549
2017	0.997910022735596
2018	0.999830007553101
2019	0.998409986495972
2020	0.999859988689423
2021	1.00498998165131