Year	Percent
2005-01-01	55.4
2006-01-01	55.6
2007-01-01	55.8
2008-01-01	56.0
2009-01-01	56.6
2010-01-01	57.3
2011-01-01	57.4
2012-01-01	57.4
2013-01-01	57.3
2014-01-01	57.3
2015-01-01	57.2
2016-01-01	57.0