Year	Percent
2005-01-01	13.6
2006-01-01	12.6
2007-01-01	12.1
2008-01-01	13.2
2009-01-01	17.7
2010-01-01	17.7
2011-01-01	16.8
2012-01-01	16.8
2013-01-01	16.6
2014-01-01	15.5
2015-01-01	14.3
2016-01-01	13.3