Year	gross (GPI)
1973	0.782769978046417
1974	0.780309975147247
1975	0.833010017871857
1976	0.856079995632172
1977	0.859080016613007
1978	0.86065000295639
1979	0.854489982128143
1980	0.852580010890961
1981	0.842809975147247
1982	0.837970018386841
1983	0.842369973659515
1984	0.847019970417023
1985	0.851589977741241
1986	0.864480018615723
1987	0.876749992370605
1988	0.88221001625061
1989	0.891369998455048
1990	0.896640002727509
1991	0.905430018901825
1992	0.915149986743927
1993	0.917289972305298
1994	0.931100010871887
1995	0.937619984149933
1996	0.944260001182556
1997	0.949639976024628
1998	0.955470025539398
1999	0.963599979877472
2000	0.96806001663208
2001	0.971570014953613
2002	0.972500026226044
2003	0.974470019340515
2004	0.980960011482239
2005	0.984350025653839
2006	0.988479971885681
2007	0.989960014820099
2008	0.993680000305176
2009	0.996980011463165
2010	0.994090020656586
2011	0.996749997138977
2012	0.998239994049072
2013	0.999010026454926
2014	1.00223004817963
2015	1.00143003463745
2016	1.00457000732422
2017	1.0056699514389
2018	1.00795996189117
2019	1.00794994831085
2020	1.00663995742798