Quarter	Percent
2006-01-01	41.6
2006-04-01	45.6
2006-07-01	46.2
2006-10-01	44.9
2007-01-01	42.6
2007-04-01	45.9
2007-07-01	46.2
2007-10-01	43.9
2008-01-01	42.4
2008-04-01	46.3
2008-07-01	46.5
2008-10-01	44.2
2009-01-01	41.4
2009-04-01	44.7
2009-07-01	45.9
2009-10-01	44.9
2010-01-01	43.8
2010-04-01	47.3
2010-07-01	47.5
2010-10-01	46.5
2011-01-01	46.1
2011-04-01	49.2
2011-07-01	49.9
2011-10-01	48.4
2012-01-01	46.3
2012-04-01	49.9
2012-07-01	49.9
2012-10-01	49.5
2013-01-01	47.9
2013-04-01	50.8
2013-07-01	50.3
2013-10-01	49.1
2014-01-01	48
2014-04-01	50.8
2014-07-01	50.2
2014-10-01	49.1
2015-01-01	48.4
2015-04-01	51.1
2015-07-01	51.1
2015-10-01	50.0
2016-01-01	49.4
2016-04-01	52.0
2016-07-01	51.1
2016-10-01	50.1
2017-01-01	49.5
2017-04-01	52.2
2017-07-01	52.6
2017-10-01	51.9
2018-01-01	51.1
2018-04-01	52.7