Year	gross (GPI)
1971	0.929799973964691
1972	0.919770002365112
1973	1.01689004898071
1974	1.09035003185272
1975	1.1492999792099
1976	1.18444001674652
1977	1.21869003772736
1978	1.21740996837616
1979	1.23108994960785
1980	1.23804998397827
1981	1.2491500377655
1982	1.25302994251251
1983	1.2333699464798
1984	1.23342001438141
1985	1.2372100353241
1986	1.24211001396179
1987	1.24589002132416
1988	1.25151002407074
1989	1.2537100315094
1990	1.32693004608154
1991	1.25344002246857
1992	1.26668000221252
1993	1.23702001571655
1994	1.26911997795105
1995	1.2913099527359
1996	1.31081998348236
1997	1.31510996818542
1998	1.26841998100281
1999	1.27302002906799
2000	1.28594994544983
2001	1.30027997493744
2002	1.29723000526428
2003	1.2948499917984
2004	1.28750002384186
2005	1.2873500585556
2006	1.28480994701385
2007	1.2835099697113
2008	1.28917002677917
2009	1.29865002632141
2010	1.33747005462646
2011	1.35728001594543
2012	1.35659003257751
2013	1.35608005523682
2014	1.34309005737305
2015	1.33297002315521
2016	1.33263003826141
2017	1.33334994316101
2018	1.34010004997253
2019	1.34850001335144
2020	1.3348400592804
2021	1.33688998222351
2022	1.35467994213104