Year	gross (GPI)
1970	0.870670020580292
1973	0.891589999198914
1977	0.942349970340729
1978	0.956030011177063
1979	0.937390029430389
1980	0.947719991207123
1981	0.956770002841949
1982	0.937359988689423
1985	0.958959996700287
1991	0.977670013904572
1992	0.977389991283417
1993	0.979380011558533
1995	0.9792600274086
1998	0.992709994316101
1999	0.998830020427704
2000	1.0006799697876
2001	1.00353002548218
2002	1.00310003757477
2003	1.0006799697876
2004	1.00151002407074
2005	1.00271999835968
2006	1.00327003002167
2007	1.00327003002167
2008	1.00292003154755
2009	0.999989986419678
2010	1.00209999084473
2011	1.00005996227264
2012	0.996079981327057
2013	1
2014	1.00220000743866
2015	1.00091004371643
2016	0.987860023975372
2017	0.973940014839172
2018	0.965669989585876
2019	0.961579978466034
2020	0.962400019168854
2021	0.970359981060028