Year	Measure
1990	0.711
1991	0.72
1992	0.731
1993	0.745
1994	0.752
1995	0.759
1996	0.766
1997	0.772
1998	0.779
1999	0.777
2000	0.782
2001	0.788
2002	0.789
2003	0.792
2004	0.79
2005	0.793
2006	0.797
2007	0.804
2008	0.809
2009	0.812
2010	0.818
2011	0.824
2012	0.827
2013	0.837
2014	0.841
2015	0.843