Year	gross (GPI)
1971	0.734399974346161
1972	0.835810005664825
1977	0.858060002326965
1988	0.925859987735748
2003	1.16680002212524
2004	1.03366005420685
2005	1.06067001819611
2007	1.06642997264862
2008	1.06414997577667
2009	1.11439001560211
2010	1.0210599899292
2011	1.14514005184174
2012	1.13235998153687
2013	1.10787999629974
2014	1.10083997249603
2015	1.11158001422882
2016	1.13935995101929
2017	1.1557400226593