Quarter	Percent
1998-04-01	58.2
1999-04-01	58.2
2000-04-01	57.6
2001-04-01	58.8
2002-04-01	59.3
2003-04-01	59.5
2004-04-01	59.1
2005-04-01	59.3
2006-04-01	59.8
2007-04-01	59.9
2008-04-01	61.3
2009-04-01	61.6
2010-01-01	60.0
2010-04-01	59.8
2010-07-01	60.2
2010-10-01	59.9
2011-01-01	60.4
2011-04-01	60.4
2011-07-01	60.4
2011-10-01	61.0
2012-01-01	60.8
2012-04-01	60.7
2012-07-01	61.1
2012-10-01	60.7
2013-01-01	61.0
2013-04-01	61.0
2013-07-01	61.2
2013-10-01	61.4
2014-01-01	61.2
2014-04-01	61.6
2014-07-01	61.9
2014-10-01	62.9
2015-01-01	62.2
2015-04-01	62.0
2015-07-01	62.2
2015-10-01	62.8
2016-01-01	63.1
2016-04-01	62.6
2016-07-01	62.6
2016-10-01	63.0
2017-01-01	62.9
2017-04-01	62.4
2017-07-01	62.5
2017-10-01	62.6
2018-01-01	63.0
2018-04-01	62.6