Year	Measure
1990	0.7
1991	0.71
1992	0.718
1993	0.713
1994	0.719
1995	0.728
1996	0.735
1997	0.742
1998	0.748
1999	0.755
2000	0.761
2001	0.768
2002	0.775
2003	0.781
2004	0.79
2005	0.796
2006	0.797
2007	0.804
2008	0.816
2009	0.815
2010	0.82
2011	0.826
2012	0.831
2013	0.841
2014	0.845
2015	0.847