Quarter	Percent
2005-01-01	46.5
2005-04-01	45.8
2005-07-01	45.6
2005-10-01	45.5
2006-01-01	45.6
2006-04-01	44.8
2006-07-01	44.7
2006-10-01	44.6
2007-01-01	44.8
2007-04-01	44.2
2007-07-01	44.2
2007-10-01	44.0
2008-01-01	44.2
2008-04-01	43.5
2008-07-01	43.7
2008-10-01	43.4
2009-01-01	43.4
2009-04-01	42.8
2009-07-01	43.1
2009-10-01	43.0
2010-01-01	42.9
2010-04-01	42.4
2010-07-01	42.4
2010-10-01	42.7
2011-01-01	42.6
2011-04-01	42.0
2011-07-01	42.1
2011-10-01	41.9
2012-01-01	41.9
2012-04-01	41.1
2012-07-01	41.1
2012-10-01	40.7
2013-01-01	40.8
2013-04-01	40.3
2013-07-01	40.2
2013-10-01	40.0
2014-01-01	40.1
2014-04-01	39.5
2014-07-01	39.4
2014-10-01	39.2
2015-01-01	39.4
2015-04-01	38.9
2015-07-01	38.7
2015-10-01	38.5
2016-01-01	38.4
2016-04-01	37.9
2016-07-01	37.8
2016-10-01	37.6
2017-01-01	37.5
2017-04-01	37.0