Year	Measure
1990	0.569
1991	0.575
1992	0.583
1993	0.59
1994	0.6
1995	0.608
1996	0.617
1997	0.624
1998	0.635
1999	0.646
2000	0.654
2001	0.662
2002	0.667
2003	0.673
2004	0.683
2005	0.689
2006	0.695
2007	0.701
2008	0.706
2009	0.71
2010	0.714
2011	0.717
2012	0.72
2013	0.722
2014	0.723
2015	0.725