Year	gross (GPI)
1970	0.812520027160645
1971	0.812020003795624
1972	0.814239978790283
1973	0.839630007743835
1974	0.861010015010834
1975	0.88919997215271
1976	0.911769986152649
1977	0.94173002243042
1978	0.969139993190765
1979	0.971459984779358
1980	0.97952002286911
1981	0.993350028991699
1982	0.989199995994568
1983	0.992850005626678
1984	0.988479971885681
1985	0.984149992465973
1986	0.989350020885468
1987	0.990010023117065
1988	0.986379981040955
1989	0.983749985694885
1990	0.98496001958847
1991	0.991460025310516
1992	0.989799976348877
1993	0.986670017242432
1994	0.982460021972656
1995	0.987659990787506
1996	0.984350025653839
1997	0.989650011062622
1998	0.995800018310547
1999	0.995540022850037
2000	0.995209991931915
2001	0.992529988288879
2002	0.988740026950836
2003	0.993960022926331
2004	1.00044000148773
2005	1.00375998020172
2006	0.999180018901825
2007	1.00074005126953
2008	1.00408005714417
2009	1.0081000328064
2010	1.00574994087219
2011	1.0032000541687
2012	1.00352001190186
2013	1.00608003139496
2014	1.00820004940033
2015	1.00800001621246
2016	1.00573003292084
2017	1.00258004665375
2018	1.0073299407959
2019	1.00478994846344
2020	1.00668001174927