Year	Measure
1990	0.662
1991	0.669
1992	0.676
1993	0.682
1994	0.685
1995	0.691
1996	0.695
1997	0.702
1998	0.71
1999	0.716
2000	0.721
2001	0.725
2002	0.728
2003	0.733
2004	0.74
2005	0.744
2006	0.743
2007	0.75
2008	0.755
2009	0.756
2010	0.758
2011	0.765
2012	0.773
2013	0.78
2014	0.785
2015	0.788