Year	Measure
1990	0.572
1991	0.59
1992	0.603
1993	0.614
1994	0.623
1995	0.634
1996	0.642
1997	0.648
1998	0.654
1999	0.66
2000	0.666
2001	0.674
2002	0.679
2003	0.686
2004	0.687
2005	0.692
2006	0.704
2007	0.716
2008	0.728
2009	0.735
2010	0.745
2011	0.755
2012	0.769
2013	0.77
2014	0.774
2015	0.774