Year	Measure
1990	0.726
1991	0.738
1992	0.742
1993	0.748
1994	0.756
1995	0.764
1996	0.771
1997	0.778
1998	0.785
1999	0.791
2000	0.798
2001	0.803
2002	0.808
2003	0.813
2004	0.818
2005	0.823
2006	0.826
2007	0.829
2008	0.831
2009	0.826
2010	0.824
2011	0.826
2012	0.829
2013	0.832
2014	0.836
2015	0.84