Year	gross (GPI)
1970	0.802890002727509
1971	0.80188000202179
1972	0.801180005073547
1973	0.798940002918243
1974	0.795029997825623
1975	0.824159979820251
1976	0.841189980506897
1977	0.84510999917984
1978	0.844539999961853
1979	0.844730019569397
1980	0.847270011901855
1981	0.848089993000031
1982	0.846279978752136
1983	0.843219995498657
1984	0.847809970378876
1985	0.852819979190826
1986	0.865700006484985
1987	0.871290028095245
1988	0.874509990215302
1989	0.876579999923706
1990	0.881770014762878
1991	0.889890015125275
1992	0.896170020103455
1993	0.901690006256104
1994	0.905709981918335
1995	0.907840013504028
1996	0.910130023956299
1997	0.915579974651337
1998	0.91813999414444
1999	0.922710001468658
2000	0.923500001430511
2001	0.928449988365173
2002	0.9305499792099
2003	0.95074999332428
2004	0.951799988746643
2005	0.954339981079102
2006	0.958519995212555
2007	0.961099982261658
2008	0.967700004577637
2009	0.972410023212433
2010	0.974799990653992
2011	0.976580023765564
2012	0.980780005455017
2013	0.997510015964508
2014	0.99752002954483
2015	0.999339997768402
2016	1.00724995136261
2017	1.00487995147705
2018	0.982209980487823
2019	0.983560025691986
2020	0.982529997825623