Year	Measure
1999	0.338
2000	0.386
2001	0.376
2002	0.373
2003	0.335
2004	0.372
2005	0.377
2006	0.383
2007	0.394
2008	0.4
2009	0.403
2010	0.406
2011	0.416
2012	0.419
2013	0.426
2014	0.427
2015	0.427