Year	Measure
1990	0.454
1991	0.457
1992	0.46
1993	0.464
1994	0.468
1995	0.471
1996	0.476
1997	0.479
1998	0.483
1999	0.488
2000	0.497
2001	0.501
2002	0.504
2003	0.509
2004	0.514
2005	0.521
2006	0.527
2007	0.531
2008	0.533
2009	0.542
2010	0.546
2011	0.553
2012	0.559
2013	0.562
2014	0.565
2015	0.574