Year	gross (GPI)
1970	0.82192999124527
1971	0.830429971218109
1972	0.829500019550323
1973	0.83227002620697
1974	0.840950012207031
1975	0.851610004901886
1976	0.860220015048981
1977	0.87610000371933
1978	0.880739986896515
1979	0.877390027046204
1981	0.930090010166168
1982	0.933179974555969
1983	0.937579989433289
1984	0.944750010967255
1985	0.950219988822937
1986	0.962840020656586
1987	0.975160002708435
1988	0.982290029525757
1989	0.993359982967377
1990	1.00051999092102
1991	0.975780010223389
1992	0.995620012283325
1995	0.981069982051849
1996	0.98063999414444
1998	0.979510009288788
1999	0.976010024547577
2000	0.973399996757507
2001	0.973140001296997
2002	0.977169990539551
2003	0.979399979114532
2012	0.98005998134613
2013	0.978720009326935
2014	0.978200018405914
2015	0.979740023612976
2016	0.983410000801086
2017	0.992219984531403
2018	0.996640026569366
2019	0.999170005321503
2020	1.00511002540588
2021	1.00537383556366