Quarter	Percent
2005-01-01	14.8
2005-04-01	13.9
2005-07-01	13.5
2005-10-01	13.0
2006-01-01	13.8
2006-04-01	12.7
2006-07-01	12.5
2006-10-01	12.2
2007-01-01	12.8
2007-04-01	12.1
2007-07-01	12.1
2007-10-01	12.0
2008-01-01	12.9
2008-04-01	12.7
2008-07-01	13.3
2008-10-01	14.6
2009-01-01	17.4
2009-04-01	18.0
2009-07-01	18.0
2009-10-01	18.2
2010-01-01	19.5
2010-04-01	17.9
2010-07-01	17.1
2010-10-01	17.0
2011-01-01	17.6
2011-04-01	16.7
2011-07-01	16.6
2011-10-01	16.4
2012-01-01	17.5
2012-04-01	16.8
2012-07-01	16.6
2012-10-01	16.4
2013-01-01	17.7
2013-04-01	16.8
2013-07-01	16.5
2013-10-01	15.5
2014-01-01	16.7
2014-04-01	15.6
2014-07-01	15.4
2014-10-01	14.5
2015-01-01	15.3
2015-04-01	14.5
2015-07-01	13.8
2015-10-01	13.6
2016-01-01	14.0
2016-04-01	13.3
2016-07-01	13.1
2016-10-01	13.0
2017-01-01	13.2
2017-04-01	12.3
2017-07-01	12.2