Year	gross (GPI)
1972	1.04322004318237
1973	1.03716003894806
1974	1.0304399728775
1989	1.04502999782562
1990	1.04373002052307
1991	1.03649997711182
1992	1.03398001194
1993	1.00198996067047
1994	1.00049996376038
1995	1.00577998161316
1996	1.00350999832153
1997	0.999840021133423
1998	1.00232994556427
1999	0.994090020656586
2000	0.985549986362457
2001	0.979059994220734
2002	0.972280025482178
2003	0.961830019950867
2004	1.01285994052887
2005	0.993939995765686
2006	0.986800014972687
2007	0.989679992198944
2008	0.994799971580505
2009	0.996519982814789
2010	0.994310021400452
2011	0.993629992008209
2012	0.990000009536743
2013	0.964299976825714
2014	0.961920022964478
2015	0.963190019130707
2016	0.966889977455139
2017	0.967459976673126
2018	0.971669971942902
2019	0.971050024032593
2020	0.986429989337921