Year	Measure
1990	0.7
1991	0.696
1992	0.696
1993	0.696
1994	0.697
1995	0.702
1996	0.702
1997	0.704
1998	0.709
1999	0.709
2000	0.713
2001	0.723
2002	0.729
2003	0.738
2004	0.745
2005	0.75
2006	0.755
2007	0.761
2008	0.768
2009	0.77
2010	0.775
2011	0.778
2012	0.781
2013	0.787
2014	0.792
2015	0.794