Year	Measure
1990	0.67
1991	0.671
1992	0.671
1993	0.673
1994	0.677
1995	0.682
1996	0.688
1997	0.696
1998	0.703
1999	0.709
2000	0.715
2001	0.721
2002	0.729
2003	0.736
2004	0.745
2005	0.751
2006	0.76
2007	0.767
2008	0.773
2009	0.772
2010	0.774
2011	0.772
2012	0.773
2013	0.778
2014	0.779
2015	0.78