Quarter	Percent
1999-01-01	63.2
2000-01-01	62.9
2001-01-01	62.7
2002-01-01	62.9
2003-01-01	63.1
2003-04-01	62.9
2003-07-01	63.3
2003-10-01	63.1
2004-01-01	62.9
2004-04-01	62.7
2004-07-01	63.1
2004-10-01	62.8
2005-01-01	62.4
2005-04-01	62.5
2005-07-01	62.8
2005-10-01	62.5
2006-01-01	62.2
2006-04-01	62.3
2006-07-01	62.7
2006-10-01	62
2007-01-01	62.1
2007-04-01	62
2007-07-01	62.6
2007-10-01	62
2008-01-01	61.9
2008-04-01	62
2008-07-01	62.3
2008-10-01	62.3
2009-01-01	62.2
2009-04-01	62.3
2009-07-01	62.1
2009-10-01	62.2
2010-01-01	62.1
2010-04-01	62
2010-07-01	62.1
2010-10-01	61.9
2011-01-01	61.6
2011-04-01	61.7
2011-07-01	61.7
2011-10-01	61.7
2012-01-01	61.6
2012-04-01	61.7
2012-07-01	61.9
2012-10-01	62.1
2013-01-01	61.7
2013-04-01	61.7
2013-07-01	61.7
2013-10-01	61.2
2014-01-01	61.1
2014-04-01	60.9
2014-07-01	60.9
2014-10-01	61.1
2015-01-01	60.9
2015-04-01	60.9
2015-07-01	60.9
2015-10-01	60.9
2016-01-01	60.8
2016-04-01	60.6
2016-07-01	60.5
2016-10-01	60.7
2017-01-01	60.0
2017-04-01	60.6
2017-07-01	60.8
2017-10-01	60.6
2018-01-01	60.3
2018-04-01	60.2