Year	Measure
1990	0.378
1991	0.386
1992	0.394
1993	0.398
1994	0.405
1995	0.41
1996	0.419
1997	0.426
1998	0.432
1999	0.439
2000	0.446
2001	0.447
2002	0.457
2003	0.463
2004	0.469
2005	0.476
2006	0.486
2007	0.492
2008	0.502
2009	0.515
2010	0.529
2011	0.538
2012	0.545
2013	0.551
2014	0.555
2015	0.558