Year	Measure
1990	0.577
1991	0.581
1992	0.587
1993	0.591
1994	0.595
1995	0.6
1996	0.609
1997	0.617
1998	0.627
1999	0.636
2000	0.644
2001	0.653
2002	0.663
2003	0.673
2004	0.68
2005	0.686
2006	0.69
2007	0.697
2008	0.705
2009	0.714
2010	0.724
2011	0.732
2012	0.737
2013	0.741
2014	0.743
2015	0.745