Year	gross (GPI)
1971	1.00817000865936
1972	0.959270000457764
1973	1.01154005527496
1983	1.0939199924469
1985	1.02716994285583
1986	1.03305995464325
1998	0.973089993000031
1999	0.977419972419739
2000	0.968540012836456
2002	1.00735998153687
2003	1.00753998756409
2004	0.948339998722076
2005	0.949919998645782
2006	0.949970006942749
2007	0.935689985752106
2008	0.932709991931915
2009	0.863529980182648
2010	0.881240010261536
2011	0.905449986457825
2012	0.903829991817474
2013	0.908079981803894
2014	0.906599998474121
2015	0.912419974803925
2016	0.923139989376068
2017	0.932510018348694
2018	0.941760003566742
2019	0.952229976654053
2020	0.956539988517761
2021	0.970000028610229