Year	Measure
1990	0.7
1991	0.685
1992	0.677
1993	0.677
1994	0.68
1995	0.686
1996	0.694
1997	0.695
1998	0.697
1999	0.703
2000	0.708
2001	0.714
2002	0.722
2003	0.733
2004	0.745
2005	0.755
2006	0.766
2007	0.78
2008	0.795
2009	0.797
2010	0.798
2011	0.797
2012	0.794
2013	0.797
2014	0.798
2015	0.802