Year	Measure
1990	0.428
1991	0.432
1992	0.439
1993	0.445
1994	0.453
1995	0.46
1996	0.468
1997	0.474
1998	0.481
1999	0.489
2000	0.494
2001	0.499
2002	0.505
2003	0.518
2004	0.526
2005	0.536
2006	0.546
2007	0.556
2008	0.563
2009	0.569
2010	0.58
2011	0.59
2012	0.599
2013	0.607
2014	0.615
2015	0.624