Year	Measure
1990	0.648
1991	0.652
1992	0.656
1993	0.662
1994	0.668
1995	0.67
1996	0.676
1997	0.683
1998	0.689
1999	0.694
2000	0.7
2001	0.703
2002	0.708
2003	0.714
2004	0.719
2005	0.723
2006	0.731
2007	0.735
2008	0.738
2009	0.739
2010	0.745
2011	0.748
2012	0.753
2013	0.754
2014	0.758
2015	0.762