Quarter	Percent
1999-04-01	44.3
2000-04-01	42.9
2001-04-01	42.6
2002-04-01	41.4
2003-01-01	42.2
2003-04-01	42.2
2003-07-01	42.2
2003-10-01	42.2
2004-01-01	41.5
2004-04-01	41.5
2004-07-01	41.5
2004-10-01	41.5
2005-01-01	40.9
2005-04-01	40.9
2005-07-01	40.9
2005-10-01	40.9
2006-01-01	40.9
2006-04-01	40.9
2006-07-01	40.9
2006-10-01	40.9
2007-01-01	39.8
2007-04-01	41
2007-07-01	39.7
2007-10-01	40.2
2008-01-01	41.3
2008-04-01	39.2
2008-07-01	39.8
2008-10-01	41.3
2009-01-01	38.8
2009-04-01	38.1
2009-07-01	38.6
2009-10-01	39.1
2010-01-01	39.2
2010-04-01	39.7
2010-07-01	38.5
2010-10-01	38.7
2011-01-01	38
2011-04-01	40.2
2011-07-01	39.5
2011-10-01	39.8
2012-01-01	38.2
2012-04-01	38.7
2012-07-01	36.8
2012-10-01	37.4
2013-01-01	37.4
2013-04-01	37.8
2013-07-01	36.8
2013-10-01	36.9
2014-01-01	36.2
2014-04-01	37.3
2014-07-01	36.8
2014-10-01	35.6
2015-01-01	34.6
2015-04-01	35.0
2015-07-01	35.2
2015-10-01	36.1
2016-01-01	36.7
2016-04-01	36.7
2016-07-01	36.1
2016-10-01	35.7
2017-01-01	37.3
2017-04-01	37.3
2017-07-01	35.4
2017-10-01	36.2
2018-01-01	35.3
2018-04-01	36.3