Year	Measure
1990	0.703
1991	0.701
1992	0.706
1993	0.719
1994	0.733
1995	0.741
1996	0.745
1997	0.747
1998	0.754
1999	0.761
2000	0.769
2001	0.775
2002	0.784
2003	0.793
2004	0.795
2005	0.802
2006	0.809
2007	0.812
2008	0.816
2009	0.817
2010	0.821
2011	0.823
2012	0.824
2013	0.834
2014	0.834
2015	0.836