Year	Measure
1990	0.271
1991	0.275
1992	0.278
1993	0.282
1994	0.286
1995	0.29
1996	0.294
1997	0.302
1998	0.309
1999	0.316
2000	0.322
2001	0.329
2002	0.338
2003	0.325
2004	0.346
2005	0.356
2006	0.364
2007	0.371
2008	0.376
2009	0.38
2010	0.385
2011	0.396
2012	0.406
2013	0.412
2014	0.414
2015	0.414