Quarter	Percent
1999-04-01	54.4
2000-04-01	55.7
2001-04-01	56.3
2002-04-01	57
2003-01-01	55.6
2003-04-01	55.6
2003-07-01	55.6
2003-10-01	55.6
2004-01-01	55.5
2004-04-01	55.5
2004-07-01	55.5
2004-10-01	55.5
2005-01-01	56.5
2005-04-01	56.5
2005-07-01	56.5
2005-10-01	56.5
2006-01-01	56.3
2006-04-01	56.3
2006-07-01	56.3
2006-10-01	56.3
2007-01-01	57.5
2007-04-01	56.7
2007-07-01	57.9
2007-10-01	57.5
2008-01-01	56.2
2008-04-01	57.7
2008-07-01	56.9
2008-10-01	55.6
2009-01-01	57.7
2009-04-01	58.7
2009-07-01	58.7
2009-10-01	57.6
2010-01-01	57.8
2010-04-01	57.8
2010-07-01	59.1
2010-10-01	58.5
2011-01-01	58.8
2011-04-01	56.6
2011-07-01	57.9
2011-10-01	57.4
2012-01-01	58.2
2012-04-01	58.8
2012-07-01	59.6
2012-10-01	59.4
2013-01-01	59.2
2013-04-01	58.3
2013-07-01	59.6
2013-10-01	59.2
2014-01-01	59.7
2014-04-01	59.6
2014-07-01	59.1
2014-10-01	60.9
2015-01-01	60.6
2015-04-01	61.5
2015-07-01	59.8
2015-10-01	59.9
2016-01-01	59.5
2016-04-01	59.4
2016-07-01	59.4
2016-10-01	60.6
2017-01-01	58.9
2017-04-01	59.3
2017-07-01	61.1
2017-10-01	60.4
2018-01-01	61.1
2018-04-01	60.2