Year	Measure
1990	0.69
1991	0.684
1992	0.682
1993	0.676
1994	0.668
1995	0.665
1996	0.666
1997	0.67
1998	0.672
1999	0.676
2000	0.685
2001	0.7
2002	0.714
2003	0.725
2004	0.737
2005	0.747
2006	0.754
2007	0.758
2008	0.758
2009	0.763
2010	0.766
2011	0.774
2012	0.782
2013	0.789
2014	0.793
2015	0.794