Quarter	Percent
1999-01-01	60.5
2000-01-01	61.5
2001-01-01	62.5
2002-01-01	62.3
2003-01-01	62.6
2003-04-01	62.8
2003-07-01	63.3
2003-10-01	62.4
2004-01-01	62.2
2004-04-01	62.5
2004-07-01	63.0
2004-10-01	62.1
2005-01-01	61.8
2005-04-01	62.4
2005-07-01	62.8
2005-10-01	62.0
2006-01-01	61.5
2006-04-01	62.2
2006-07-01	62.9
2006-10-01	61.8
2007-01-01	61.7
2007-04-01	62.4
2007-07-01	63.1
2007-10-01	62.5
2008-01-01	62.4
2008-04-01	63.0
2008-07-01	63.3
2008-10-01	62.7
2009-01-01	61.8
2009-04-01	62.0
2009-07-01	62.0
2009-10-01	61.2
2010-01-01	61.1
2010-04-01	61.7
2010-07-01	62.1
2010-10-01	61.6
2011-01-01	61.2
2011-04-01	61.7
2011-07-01	61.9
2011-10-01	61.0
2012-01-01	60.6
2012-04-01	61.3
2012-07-01	61.6
2012-10-01	60.9
2013-01-01	60.1
2013-04-01	60.7
2013-07-01	61.1
2013-10-01	60.2
2014-01-01	59.3
2014-04-01	59.8
2014-07-01	60.0
2014-10-01	59.4
2015-01-01	59.0
2015-04-01	59.5
2015-07-01	59.7
2015-10-01	59.3
2016-01-01	59.0
2016-04-01	59.7
2016-07-01	60.0
2016-10-01	59.4
2017-01-01	59.1
2017-04-01	60.1
2017-07-01	60.4
2017-10-01	60.1
2018-01-01	59.7
2018-04-01	60.2