Year	Measure
1990	0.805
1991	0.809
1992	0.824
1993	0.838
1994	0.844
1995	0.851
1996	0.856
1997	0.861
1998	0.865
1999	0.869
2000	0.873
2001	0.875
2002	0.878
2003	0.88
2004	0.861
2005	0.865
2006	0.871
2007	0.874
2008	0.876
2009	0.878
2010	0.884
2011	0.886
2012	0.889
2013	0.89
2014	0.895
2015	0.896