Year	Measure
1990	0.598
1991	0.601
1992	0.604
1993	0.61
1994	0.612
1995	0.619
1996	0.626
1997	0.629
1998	0.635
1999	0.64
2000	0.645
2001	0.653
2002	0.659
2003	0.665
2004	0.671
2005	0.677
2006	0.682
2007	0.688
2008	0.691
2009	0.69
2010	0.693
2011	0.698
2012	0.7
2013	0.701
2014	0.702
2015	0.704