Year	Measure
1990	0.728
1991	0.723
1992	0.715
1993	0.708
1994	0.712
1995	0.722
1996	0.733
1997	0.746
1998	0.758
1999	0.764
2000	0.781
2001	0.791
2002	0.798
2003	0.805
2004	0.812
2005	0.822
2006	0.829
2007	0.835
2008	0.836
2009	0.833
2010	0.838
2011	0.85
2012	0.856
2013	0.86
2014	0.863
2015	0.865