Quarter	Percent
2005-01-01	57.3
2005-04-01	56.6
2005-07-01	56.3
2005-10-01	56.1
2006-01-01	56.2
2006-04-01	55.4
2006-07-01	55.0
2006-10-01	54.9
2007-01-01	55.2
2007-04-01	54.5
2007-07-01	54.6
2007-10-01	54.2
2008-01-01	54.5
2008-04-01	53.8
2008-07-01	54.0
2008-10-01	53.6
2009-01-01	53.6
2009-04-01	52.7
2009-07-01	52.8
2009-10-01	52.8
2010-01-01	52.7
2010-04-01	52.0
2010-07-01	51.8
2010-10-01	52.1
2011-01-01	52.0
2011-04-01	51.2
2011-07-01	51.2
2011-10-01	51.1
2012-01-01	51.0
2012-04-01	50.2
2012-07-01	50.4
2012-10-01	50.0
2013-01-01	49.9
2013-04-01	49.3
2013-07-01	49.3
2013-10-01	49.0
2014-01-01	49.0
2014-04-01	48.4
2014-07-01	48.5
2014-10-01	48.2
2015-01-01	48.3
2015-04-01	47.8
2015-07-01	47.6
2015-10-01	47.2
2016-01-01	47.1
2016-04-01	46.7
2016-07-01	46.7
2016-10-01	46.3
2017-01-01	46.1
2017-04-01	45.7