Year	gross (GPI)
1971	0.956459999084473
1972	0.952319979667664
1973	0.954919993877411
1974	0.958509981632233
1989	0.980069994926453
1990	0.979770004749298
1991	0.996580004692078
1992	1.00325000286102
1993	0.997659981250763
1994	1.01565003395081
1995	1.01724994182587
1996	1.01162004470825
1997	1.00107002258301
1998	1.00839996337891
1999	1.01060998439789
2000	1.01130998134613
2001	1.01004004478455
2002	1.01094996929169
2003	1.01096999645233
2004	1.00909996032715
2005	1.00849997997284
2006	1.00404000282288
2007	0.99711000919342
2008	0.992399990558624
2009	0.99370002746582
2010	0.988940000534058
2011	0.98565000295639
2012	0.987150013446808
2015	0.994530022144318
2016	0.993669986724854
2017	0.997160017490387
2018	0.998149991035461
2019	0.998179972171783
2020	0.999409973621368