Quarter	Percent
2005-01-01	14.2
2005-04-01	13.6
2005-07-01	13.3
2005-10-01	12.8
2006-01-01	13.3
2006-04-01	12.5
2006-07-01	12.6
2006-10-01	12.1
2007-01-01	12.4
2007-04-01	11.8
2007-07-01	12.1
2007-10-01	11.7
2008-01-01	12.3
2008-04-01	12.5
2008-07-01	13.2
2008-10-01	13.6
2009-01-01	16.0
2009-04-01	16.8
2009-07-01	17.3
2009-10-01	16.8
2010-01-01	17.7
2010-04-01	17.0
2010-07-01	16.7
2010-10-01	16.3
2011-01-01	16.9
2011-04-01	16.3
2011-07-01	16.5
2011-10-01	15.8
2012-01-01	16.7
2012-04-01	16.3
2012-07-01	16.4
2012-10-01	16.1
2013-01-01	17.0
2013-04-01	16.3
2013-07-01	16.2
2013-10-01	15.2
2014-01-01	16.0
2014-04-01	15.0
2014-07-01	15.2
2014-10-01	14.3
2015-01-01	14.7
2015-04-01	14.1
2015-07-01	13.8
2015-10-01	13.1
2016-01-01	13.4
2016-04-01	13.0
2016-07-01	13.0
2016-10-01	12.4
2017-01-01	12.6
2017-04-01	12.0
2017-07-01	12.0