Quarter	Percent
2004-01-01	14.5
2004-04-01	13.9
2004-07-01	13.5
2004-10-01	13.4
2005-01-01	14.8
2005-04-01	13.8
2005-07-01	13.3
2005-10-01	12.8
2006-01-01	13.7
2006-04-01	12.8
2006-07-01	12.7
2006-10-01	12.3
2007-01-01	12.9
2007-04-01	12.4
2007-07-01	12.4
2007-10-01	12.4
2008-01-01	13.3
2008-04-01	13.4
2008-07-01	14.0
2008-10-01	14.9
2009-01-01	18.0
2009-04-01	18.5
2009-07-01	18.6
2009-10-01	19.2
2010-01-01	20.8
2010-04-01	19.0
2010-07-01	17.9
2010-10-01	17.7
2011-01-01	18.4
2011-04-01	17.4
2011-07-01	17.3
2011-10-01	17.2
2012-01-01	18.3
2012-04-01	17.6
2012-07-01	17.2
2012-10-01	16.7
2013-01-01	18.1
2013-04-01	17.5
2013-07-01	16.9
2013-10-01	15.5
2014-01-01	17.0
2014-04-01	15.4
2014-07-01	15.1
2014-10-01	14.0
2015-01-01	15.1
2015-04-01	14.2
2015-07-01	13.4
2015-10-01	13.2
2016-01-01	13.6
2016-04-01	12.7
2016-07-01	12.8
2016-10-01	12.5
2017-01-01	12.7
2017-04-01	11.6
2017-07-01	11.5