Year	Measure
1990	0.367
1991	0.366
1992	0.367
1993	0.365
1994	0.365
1995	0.371
1996	0.373
1997	0.372
1998	0.376
1999	0.378
2000	0.381
2001	0.397
2002	0.401
2003	0.408
2004	0.415
2005	0.422
2006	0.425
2007	0.435
2008	0.444
2009	0.449
2010	0.455
2011	0.463
2012	0.474
2013	0.483
2014	0.491
2015	0.494