Year	Measure
1990	0.714
1991	0.713
1992	0.7
1993	0.684
1994	0.688
1995	0.694
1996	0.697
1997	0.703
1998	0.707
1999	0.702
2000	0.709
2001	0.715
2002	0.715
2003	0.72
2004	0.73
2005	0.739
2006	0.743
2007	0.749
2008	0.754
2009	0.755
2010	0.757
2011	0.767
2012	0.766
2013	0.771
2014	0.775
2015	0.776