Year	gross (GPI)
1970	0.78413999080658
1971	0.782989978790283
1972	0.781300008296967
1973	0.779699981212616
1974	0.777350008487701
1975	0.818340003490448
1976	0.841480016708374
1977	0.845120012760162
1978	0.84077000617981
1979	0.841489970684052
1980	0.842880010604858
1981	0.841530025005341
1982	0.837430000305176
1983	0.838670015335083
1984	0.842400014400482
1985	0.849449992179871
1986	0.867139995098114
1987	0.875329971313477
1988	0.880770027637482
1989	0.880569994449615
1990	0.888830006122589
1991	0.899079978466034
1992	0.90666002035141
1993	0.914789974689484
1994	0.919160008430481
1995	0.923489987850189
1996	0.925970017910004
1997	0.932929992675781
1998	0.935999989509583
1999	0.94037002325058
2000	0.94225001335144
2001	0.947730004787445
2002	0.952030003070831
2003	0.980840027332306
2004	0.983349978923798
2005	0.980840027332306
2006	0.980929970741272
2007	0.980300009250641
2008	0.988870024681091
2009	0.993430018424988
2010	0.994050025939941
2011	0.994000017642975
2012	0.996789991855621
2013	1.0246000289917
2014	1.02496004104614
2015	1.02576994895935
2016	1.04251003265381
2017	1.03838002681732
2018	0.999440014362335
2019	0.99889999628067
2020	0.997850000858307