Quarter	Percent
2005-01-01	51.0
2005-04-01	50.7
2005-07-01	50.7
2005-10-01	50.7
2006-01-01	50.0
2006-04-01	50.6
2006-07-01	50.6
2006-10-01	49.6
2007-01-01	50.2
2007-04-01	50.6
2007-07-01	50.8
2007-10-01	49.1
2008-01-01	49.6
2008-04-01	49.3
2008-07-01	51.5
2008-10-01	51.7
2009-01-01	51.4
2009-04-01	52.1
2009-07-01	52.5
2009-10-01	52.2
2010-01-01	51.7
2010-04-01	52.0
2010-07-01	53.1
2010-10-01	53.3
2011-01-01	52.4
2011-04-01	53.0
2011-07-01	53.1
2011-10-01	52.4
2012-01-01	53.1
2012-04-01	53.5
2012-07-01	53.4
2012-10-01	52.8
2013-01-01	52.8
2013-04-01	53.1
2013-07-01	52.9
2013-10-01	53.0
2014-01-01	53.8
2014-04-01	53.8
2014-07-01	54.1
2014-10-01	53.8
2015-01-01	53.7
2015-04-01	54.5
2015-07-01	54.7
2015-10-01	54.9
2016-01-01	55.5
2016-04-01	55.7
2016-07-01	55.6
2016-10-01	55.7
2017-01-01	55.4
2017-04-01	56.3
2017-07-01	55.8
2017-10-01	55.8
2018-01-01	55.7
2018-04-01	55.9