Quarter	Percent
2005-01-01	56.7
2005-04-01	55.4
2005-07-01	54.1
2005-10-01	55.6
2006-01-01	56.8
2006-04-01	55.6
2006-07-01	54.2
2006-10-01	55.8
2007-01-01	56.7
2007-04-01	56.0
2007-07-01	54.6
2007-10-01	56.0
2008-01-01	57.0
2008-04-01	55.6
2008-07-01	54.8
2008-10-01	56.7
2009-01-01	57.5
2009-04-01	56.4
2009-07-01	55.2
2009-10-01	57.4
2010-01-01	58.2
2010-04-01	57.1
2010-07-01	55.9
2010-10-01	58.0
2011-01-01	58.6
2011-04-01	57.2
2011-07-01	56.1
2011-10-01	57.7
2012-01-01	58.7
2012-04-01	57.1
2012-07-01	56.1
2012-10-01	57.6
2013-01-01	58.4
2013-04-01	57.0
2013-07-01	56.2
2013-10-01	57.5
2014-01-01	58.4
2014-04-01	57.2
2014-07-01	56.2
2014-10-01	57.5
2015-01-01	58.5
2015-04-01	57.0
2015-07-01	56.0
2015-10-01	57.4
2016-01-01	58.1
2016-04-01	56.9
2016-07-01	55.6
2016-10-01	57.4
2017-01-01	57.9
2017-04-01	56.8