Year	gross (GPI)
1975	0.813459992408752
1976	0.840200006961823
1977	0.844089984893799
1978	0.84579998254776
1979	0.838129997253418
1980	0.834739983081818
1981	0.822759985923767
1982	0.816330015659332
1983	0.820720016956329
1984	0.825500011444092
1985	0.830900013446808
1986	0.845399975776672
1987	0.859189987182617
1988	0.865899980068207
1989	0.876030027866364
1990	0.881730020046234
1991	0.892009973526001
1992	0.903180003166199
1993	0.905600011348724
1994	0.921589970588684
1995	0.928849995136261
1996	0.936429977416992
1997	0.942749977111816
1998	0.949540019035339
1999	0.958769977092743
2000	0.96381002664566
2001	0.967679977416992
2002	0.968710005283356
2003	0.970939993858337
2004	0.978320002555847
2005	0.982110023498535
2006	0.986800014972687
2007	0.988590002059937
2008	0.992720007896423
2009	0.996490001678467
2010	0.993409991264343
2011	0.996429979801178
2012	0.998160004615784
2013	0.999140024185181
2014	1.002769947052
2015	1.00204002857208
2016	1.00547003746033
2017	1.00652003288269
2018	1.00857996940613
2019	1.00867998600006
2020	1.00708997249603