Quarter	Percent
1999-01-01	45.8
2000-01-01	45.5
2001-01-01	45.5
2002-01-01	45.2
2003-01-01	43.8
2003-04-01	44.0
2003-07-01	43.9
2003-10-01	44.1
2004-01-01	43.9
2004-04-01	43.8
2004-07-01	43.3
2004-10-01	43.4
2005-01-01	43.4
2005-04-01	43.2
2005-07-01	43.1
2005-10-01	43.3
2006-01-01	43.2
2006-04-01	43.4
2006-07-01	42.7
2006-10-01	42.7
2007-01-01	42.8
2007-04-01	42.6
2007-07-01	42.3
2007-10-01	42.2
2008-01-01	42.4
2008-04-01	42.2
2008-07-01	42.0
2008-10-01	42.0
2009-01-01	41.9
2009-04-01	41.4
2009-07-01	41.5
2009-10-01	41.7
2010-01-01	41.6
2010-04-01	41.6
2010-07-01	41.4
2010-10-01	41.6
2011-01-01	41.8
2011-04-01	41.7
2011-07-01	41.6
2011-10-01	41.5
2012-01-01	41.6
2012-04-01	41.4
2012-07-01	41.4
2012-10-01	41.1
2013-01-01	41.4
2013-04-01	41.2
2013-07-01	41
2013-10-01	40.9
2014-01-01	41.3
2014-04-01	41.3
2014-07-01	41.3
2014-10-01	41.2
2015-01-01	41.5
2015-04-01	41.5
2015-07-01	41.1
2015-10-01	41.3
2016-01-01	41.4
2016-04-01	41.6
2016-07-01	41.3
2016-10-01	41.6
2017-01-01	41.9
2017-04-01	41.7
2017-07-01	41.8
2017-10-01	41.7
2018-01-01	41.6
2018-04-01	41.6