Year	Measure
1990	0.754
1991	0.751
1992	0.752
1993	0.763
1994	0.775
1995	0.783
1996	0.796
1997	0.8
1998	0.804
1999	0.808
2000	0.809
2001	0.807
2002	0.815
2003	0.826
2004	0.83
2005	0.835
2006	0.83
2007	0.825
2008	0.828
2009	0.825
2010	0.827
2011	0.837
2012	0.843
2013	0.854
2014	0.855
2015	0.856