Year	Measure
1990	0.733
1991	0.736
1992	0.741
1993	0.778
1994	0.782
1995	0.784
1996	0.788
1997	0.791
1998	0.798
1999	0.798
2000	0.8
2001	0.805
2002	0.815
2003	0.823
2004	0.826
2005	0.829
2006	0.836
2007	0.844
2008	0.849
2009	0.853
2010	0.847
2011	0.85
2012	0.85
2013	0.85
2014	0.854
2015	0.856