Year	Measure
1990	0.586
1991	0.587
1992	0.589
1993	0.591
1994	0.594
1995	0.597
1996	0.605
1997	0.609
1998	0.613
1999	0.618
2000	0.622
2001	0.625
2002	0.631
2003	0.636
2004	0.642
2005	0.646
2006	0.648
2007	0.655
2008	0.661
2009	0.662
2010	0.669
2011	0.666
2012	0.671
2013	0.676
2014	0.679
2015	0.682