Year	Measure
1990	0.653
1991	0.658
1992	0.667
1993	0.673
1994	0.679
1995	0.684
1996	0.687
1997	0.693
1998	0.699
1999	0.702
2000	0.708
2001	0.712
2002	0.715
2003	0.719
2004	0.723
2005	0.727
2006	0.734
2007	0.74
2008	0.747
2009	0.749
2010	0.752
2011	0.758
2012	0.762
2013	0.768
2014	0.775
2015	0.776