Year	Measure
1990	0.397
1991	0.402
1992	0.408
1993	0.414
1994	0.423
1995	0.425
1996	0.438
1997	0.445
1998	0.452
1999	0.459
2000	0.463
2001	0.468
2002	0.477
2003	0.485
2004	0.494
2005	0.503
2006	0.509
2007	0.518
2008	0.525
2009	0.535
2010	0.542
2011	0.554
2012	0.563
2013	0.573
2014	0.582
2015	0.586