Year	Measure
1990	0.389
1991	0.388
1992	0.388
1993	0.387
1994	0.387
1995	0.388
1996	0.389
1997	0.392
1998	0.39
1999	0.393
2000	0.395
2001	0.397
2002	0.398
2003	0.4
2004	0.406
2005	0.413
2006	0.418
2007	0.423
2008	0.431
2009	0.436
2010	0.441
2011	0.444
2012	0.452
2013	0.459
2014	0.466
2015	0.474