Year	gross (GPI)
1972	0.930779993534088
1973	0.922060012817383
1974	0.93121999502182
1975	0.958410024642944
1976	0.977789998054504
1977	0.987749993801117
1978	0.992399990558624
1979	0.99549001455307
1980	0.992739975452423
1981	0.991940021514893
1982	1.00379002094269
1983	0.992820024490356
1984	0.994660019874573
1985	0.997839987277985
1986	0.999279975891113
1987	1.00616002082825
1988	1.00133001804352
1989	0.996840000152588
1990	0.995090007781982
1991	0.994040012359619
1992	0.99686998128891
1993	0.997420012950897
1994	0.997850000858307
1995	0.997359991073608
1996	1.00218999385834
1997	1.0014899969101
1998	0.997479975223541
1999	0.996680021286011
2000	0.994199991226196
2001	0.994920015335083
2002	0.993520021438599
2003	0.991310000419617
2004	0.991029977798462
2005	0.99234002828598
2006	0.996169984340668
2007	0.995369970798492
2008	0.991800010204315
2009	0.993439972400665
2010	0.993439972400665
2011	0.992049992084503
2012	0.991599977016449
2013	0.992399990558624
2014	0.995800018310547
2015	0.994159996509552
2016	0.995559990406036
2017	0.994870007038116
2018	0.994700014591217
2019	0.994539976119995
2020	0.997009992599487