Year	gross (GPI)
1971	0.950969994068146
1972	0.99466997385025
1977	1.00906002521515
1978	1.00691998004913
1979	1.00687003135681
1980	1.00803005695343
1981	1.0720100402832
1982	1.08513998985291
1983	1.06394994258881
1984	1.02516996860504
1985	1.02205002307892
1986	0.938489973545074
1988	0.960080027580261
1993	1.03847002983093
2002	1.02286994457245
2003	0.98470002412796
2004	1.01572000980377
2005	0.997229993343353
2007	0.981389999389648
2008	0.930469989776611
2009	0.965849995613098
2010	0.990369975566864
2013	0.961449980735779
2014	0.980840027332306
2015	0.971180021762848
2016	0.991129994392395
2017	0.986729979515076
2018	1.00446999073029