Quarter	Percent
2005-01-01	43.3
2005-04-01	43.6
2005-07-01	43.7
2005-10-01	43.7
2006-01-01	44.1
2006-04-01	43.5
2006-07-01	43.5
2006-10-01	44.7
2007-01-01	43.7
2007-04-01	43.3
2007-07-01	43.1
2007-10-01	45.0
2008-01-01	44.2
2008-04-01	44.6
2008-07-01	42.0
2008-10-01	41.9
2009-01-01	42.0
2009-04-01	41.2
2009-07-01	40.7
2009-10-01	41.1
2010-01-01	41.4
2010-04-01	41.1
2010-07-01	39.7
2010-10-01	39.6
2011-01-01	40.2
2011-04-01	39.5
2011-07-01	39.3
2011-10-01	40.0
2012-01-01	39.1
2012-04-01	38.6
2012-07-01	38.6
2012-10-01	39.1
2013-01-01	39.2
2013-04-01	38.7
2013-07-01	38.9
2013-10-01	38.8
2014-01-01	38.0
2014-04-01	37.8
2014-07-01	37.2
2014-10-01	37.6
2015-01-01	37.6
2015-04-01	36.8
2015-07-01	36.4
2015-10-01	36.2
2016-01-01	35.7
2016-04-01	35.3
2016-07-01	35.3
2016-10-01	35.2
2017-01-01	35.5
2017-04-01	34.3
2017-07-01	34.7
2017-10-01	34.6
2018-01-01	34.9
2018-04-01	34.6