Year	Measure
1990	0.404
1991	0.409
1992	0.415
1993	0.418
1994	0.423
1995	0.429
1996	0.433
1997	0.437
1998	0.441
1999	0.445
2000	0.45
2001	0.457
2002	0.465
2003	0.474
2004	0.487
2005	0.501
2006	0.505
2007	0.513
2008	0.514
2009	0.521
2010	0.525
2011	0.529
2012	0.538
2013	0.542
2014	0.548
2015	0.55