Year	Percent
2005-01-01	80.5
2006-01-01	80.8
2007-01-01	81.0
2008-01-01	81.2
2009-01-01	81.2
2010-01-01	81.2
2011-01-01	81.3
2012-01-01	81.4
2013-01-01	81.5
2014-01-01	81.5
2015-01-01	81.6
2016-01-01	81.9