Quarter	Percent
2005-01-01	20.5
2005-04-01	19.9
2005-07-01	19.5
2005-10-01	20.0
2006-01-01	20.4
2006-04-01	19.7
2006-07-01	19.4
2006-10-01	19.8
2007-01-01	20.3
2007-04-01	19.7
2007-07-01	19.4
2007-10-01	19.9
2008-01-01	20.3
2008-04-01	19.6
2008-07-01	19.3
2008-10-01	20.0
2009-01-01	20.5
2009-04-01	20.1
2009-07-01	20.0
2009-10-01	20.6
2010-01-01	20.9
2010-04-01	20.3
2010-07-01	20.2
2010-10-01	20.8
2011-01-01	21.1
2011-04-01	20.5
2011-07-01	20.3
2011-10-01	20.7
2012-01-01	21.2
2012-04-01	20.4
2012-07-01	20.2
2012-10-01	20.6
2013-01-01	21.0
2013-04-01	20.4
2013-07-01	20.2
2013-10-01	20.7
2014-01-01	20.9
2014-04-01	20.4
2014-07-01	20.0
2014-10-01	20.5
2015-01-01	20.8
2015-04-01	20.3
2015-07-01	20.1
2015-10-01	20.4
2016-01-01	20.6
2016-04-01	20.0
2016-07-01	19.7
2016-10-01	20.1
2017-01-01	20.4
2017-04-01	19.8