Year	Measure
1990	0.626
1991	0.631
1992	0.636
1993	0.638
1994	0.646
1995	0.651
1996	0.655
1997	0.662
1998	0.669
1999	0.677
2000	0.686
2001	0.699
2002	0.697
2003	0.705
2004	0.712
2005	0.718
2006	0.725
2007	0.731
2008	0.735
2009	0.739
2010	0.746
2011	0.752
2012	0.757
2013	0.76
2014	0.764
2015	0.766