Year	gross (GPI)
1970	0.745589971542358
1971	0.74549001455307
1972	0.746230006217957
1973	0.746190011501312
1974	0.747460007667542
1975	0.775309979915619
1976	0.789219975471497
1977	0.793359994888306
1978	0.796169996261597
1979	0.800249993801117
1980	0.799369990825653
1981	0.797119975090027
1982	0.795130014419556
1983	0.797420024871826
1984	0.797569990158081
1985	0.799290001392365
1986	0.816879987716675
1987	0.824930012226105
1988	0.829729974269867
1989	0.834389984607697
1990	0.839309990406036
1991	0.847729980945587
1992	0.854979991912842
1993	0.861129999160767
1994	0.869889974594116
1995	0.875389993190765
1996	0.880230009555817
1997	0.887969970703125
1998	0.895079970359802
1999	0.903090000152588
2000	0.906599998474121
2001	0.910510003566742
2002	0.913980007171631
2003	0.934360027313232
2004	0.935750007629395
2005	0.941410005092621
2006	0.946179986000061
2007	0.951300024986267
2008	0.959460020065308
2009	0.967490017414093
2010	0.966799974441528
2011	0.969709992408752
2012	0.973879992961884
2013	0.990360021591187
2014	0.992590010166168
2015	0.993560016155243
2016	0.999930024147034
2017	0.998260021209717
2018	0.98497998714447
2019	0.986190021038055
2020	0.983560025691986