Year	Measure
1990	0.785
1991	0.794
1992	0.801
1993	0.806
1994	0.811
1995	0.817
1996	0.823
1997	0.831
1998	0.839
1999	0.845
2000	0.85
2001	0.855
2002	0.863
2003	0.863
2004	0.866
2005	0.87
2006	0.872
2007	0.877
2008	0.876
2009	0.878
2010	0.883
2011	0.889
2012	0.891
2013	0.895
2014	0.898
2015	0.899