Year	gross (GPI)
1971	0.983980000019073
1972	0.981949985027313
1973	0.996519982814789
1974	0.990710020065308
1975	0.99507999420166
1976	0.996129989624023
1977	1.00327003002167
1978	1.00642001628876
1979	1.00970995426178
1980	1.01231002807617
1981	1.01566994190216
1982	1.01364004611969
1983	1.02303004264832
1984	1.01726996898651
1985	1.01885998249054
1986	1.01291000843048
1987	1.01401996612549
1988	1.01364004611969
1989	1.01452004909515
1990	1.01689004898071
1991	1.01929998397827
1992	1.01709997653961
1993	1.03746998310089
1994	1.03794002532959
1995	1.0453200340271
1996	1.04335999488831
1999	1.04175996780396
2000	1.05727994441986
2001	1.06342005729675
2002	1.06831002235413
2003	1.05752003192902
2004	1.05655002593994
2005	1.06991994380951
2006	1.07474994659424
2007	1.0798100233078
2008	1.08785998821259
2009	1.08960998058319
2010	1.0833899974823
2011	1.0819000005722
2012	1.08252000808716
2013	1.08219003677368
2014	1.0798499584198
2015	1.08054995536804
2016	1.069659948349
2017	1.07024002075195
2018	1.0733699798584
2019	1.0791300535202
2020	1.08149003982544