Year	Measure
1990	0.62
1991	0.625
1992	0.625
1993	0.628
1994	0.631
1995	0.634
1996	0.636
1997	0.638
1998	0.641
1999	0.637
2000	0.633
2001	0.636
2002	0.638
2003	0.64
2004	0.64
2005	0.646
2006	0.645
2007	0.651
2008	0.652
2009	0.66
2010	0.664
2011	0.669
2012	0.678
2013	0.687
2014	0.694
2015	0.697