Quarter	Percent
1999-04-01	42.1
2000-04-01	42.5
2001-04-01	42.5
2002-04-01	42.7
2003-04-01	42.7
2004-04-01	43.1
2005-01-01	41.8
2005-04-01	41.7
2005-07-01	41.5
2005-10-01	41.4
2006-01-01	41.4
2006-04-01	41.3
2006-07-01	40.9
2006-10-01	40.6
2007-01-01	41.5
2007-04-01	41.1
2007-07-01	40.5
2007-10-01	40.4
2008-01-01	41.1
2008-04-01	41.3
2008-07-01	40.3
2008-10-01	40.4
2009-01-01	40.9
2009-04-01	40.9
2009-07-01	40.6
2009-10-01	39.9
2010-01-01	40.7
2010-04-01	40.8
2010-07-01	40.6
2010-10-01	40.4
2011-01-01	40.4
2011-04-01	40
2011-07-01	39.6
2011-10-01	39.6
2012-01-01	40.4
2012-04-01	40.1
2012-07-01	39.5
2012-10-01	39.7
2013-01-01	39.9
2013-04-01	39.6
2013-07-01	39.5
2013-10-01	39.6
2014-01-01	39.8
2014-04-01	39.8
2014-07-01	39.3
2014-10-01	39.5
2015-01-01	40.0
2015-04-01	40.1
2015-07-01	39.7
2015-10-01	39.4
2016-01-01	39.2
2016-04-01	39.3
2016-07-01	38.8
2016-10-01	38.7
2017-01-01	39.2
2017-04-01	39.1
2017-07-01	38.5
2017-10-01	38.3
2018-01-01	39.0
2018-04-01	39.1