Year	Measure
1990	0.718
1991	0.729
1992	0.74
1993	0.751
1994	0.763
1995	0.773
1996	0.783
1997	0.795
1998	0.801
1999	0.81
2000	0.82
2001	0.818
2002	0.819
2003	0.82
2004	0.821
2005	0.839
2006	0.873
2007	0.88
2008	0.887
2009	0.889
2010	0.911
2011	0.917
2012	0.92
2013	0.922
2014	0.924
2015	0.925