Year	Measure
1990	0.782
1991	0.787
1992	0.792
1993	0.797
1994	0.801
1995	0.805
1996	0.807
1997	0.81
1998	0.812
1999	0.818
2000	0.819
2001	0.82
2002	0.823
2003	0.828
2004	0.834
2005	0.837
2006	0.84
2007	0.84
2008	0.841
2009	0.845
2010	0.846
2011	0.852
2012	0.86
2013	0.863
2014	0.864
2015	0.865