Year	gross (GPI)
1970	0.647889971733093
1971	0.64614999294281
1972	0.651700019836426
1973	0.658909976482391
1974	0.665579974651337
1975	0.67289000749588
1976	0.679750025272369
1977	0.689970016479492
1978	0.700869977474213
1979	0.726610004901886
1980	0.740880012512207
1981	0.753549993038177
1982	0.762960016727448
1983	0.768249988555908
1984	0.774420022964478
1985	0.783580005168915
1986	0.792869985103607
1987	0.801419973373413
1988	0.799870014190674
1989	0.811720013618469
1990	0.817569971084595
1991	0.818019986152649
1992	0.82845002412796
1993	0.834159970283508
1994	0.836149990558624
1995	0.846480011940002
1996	0.819519996643066
1997	0.849849998950958
1998	0.857620000839233
1999	0.865660011768341
2000	0.874319970607758
2001	0.88484001159668
2002	0.891240000724792
2003	0.897440016269684
2004	0.901790022850037
2005	0.905860006809235
2006	0.906989991664886
2007	0.908940017223358
2008	0.91499000787735
2009	0.919290006160736
2010	0.922900021076202
2011	0.918039977550507
2012	0.929440021514893
2013	0.930890023708344
2014	0.936680018901825
2015	0.940949976444244
2016	0.941330015659332
2017	0.944519996643066
2018	0.945349991321564
2019	0.948260009288788
2020	0.950160026550293