Year	gross (GPI)
1976	1.01319003105164
1977	1.02917003631592
1978	0.916050016880035
1979	0.960240006446838
1980	0.952390015125275
1981	0.936869978904724
1985	0.957759976387024
1986	0.947260022163391
1991	1.00274002552032
1995	0.99957001209259
1998	0.960659980773926
1999	0.94132000207901
2000	0.958670020103455
2001	0.955860018730164
2002	0.95058000087738
2003	0.949779987335205
2004	0.943719983100891
2005	0.950540006160736
2006	0.968479990959167
2007	0.966780006885529
2009	0.977609992027283
2010	0.954370021820068
2011	0.960330009460449
2012	1.0113799571991
2013	0.983980000019073
2014	0.998369991779327
2015	1.00417995452881
2016	1.01511001586914
2017	1.01761996746063
2018	1.02182996273041
2019	1.02138996124268
2020	1.02302002906799
2021	1.01944005489349