Year	Measure
1990	0.295
1991	0.3
1992	0.309
1993	0.305
1994	0.3
1995	0.324
1996	0.328
1997	0.332
1998	0.335
1999	0.338
2000	0.34
2001	0.341
2002	0.373
2003	0.381
2004	0.396
2005	0.405
2006	0.415
2007	0.433
2008	0.434
2009	0.448
2010	0.454
2011	0.463
2012	0.47
2013	0.476
2014	0.479
2015	0.479