Year	Percent
1998-01-01	11.40
1999-01-01	11.50
2000-01-01	11.70
2001-01-01	12.00
2002-01-01	12.70
2003-01-01	12.40
2004-01-01	12.40
2005-01-01	12.20
2006-01-01	12.50
2007-01-01	12.90
2008-01-01	13.60
2009-01-01	14.80
2010-01-01	16.05
2011-01-01	16.40
2012-01-01	17.94
2013-01-01	19.16
2014-01-01	17.96
2015-01-01	18.26
2016-01-01	18.79