Year	gross (GPI)
1971	0.764519989490509
1998	0.965279996395111
1999	0.968089997768402
2000	0.965309977531433
2001	0.967830002307892
2002	0.970149993896484
2003	0.973890006542206
2004	0.97706001996994
2005	0.981779992580414
2006	0.9860799908638
2007	0.989629983901978
2008	0.990760028362274
2009	0.992380023002625
2010	0.994979977607727
2011	0.997250020503998
2012	0.991159975528717
2013	0.986109972000122
2014	0.983799993991852
2015	0.982349991798401
2016	0.982200026512146
2017	0.983070015907288
2018	0.984809994697571
2019	0.988470017910004
2020	0.994159996509552