Quarter	Percent
1999-04-01	52.7
2000-04-01	52.9
2001-04-01	53
2002-04-01	52.4
2003-04-01	51.7
2004-04-01	50.8
2005-01-01	51.5
2005-04-01	51.7
2005-07-01	52
2005-10-01	52.3
2006-01-01	52
2006-04-01	52.7
2006-07-01	53.3
2006-10-01	53.6
2007-01-01	53
2007-04-01	53.9
2007-07-01	54.5
2007-10-01	54.7
2008-01-01	54
2008-04-01	54.1
2008-07-01	55.5
2008-10-01	55.5
2009-01-01	54.3
2009-04-01	54.5
2009-07-01	54.7
2009-10-01	55.7
2010-01-01	54.6
2010-04-01	55.0
2010-07-01	55.5
2010-10-01	55.8
2011-01-01	55.7
2011-04-01	56.5
2011-07-01	57
2011-10-01	57.2
2012-01-01	56.2
2012-04-01	56.7
2012-07-01	57.3
2012-10-01	57.2
2013-01-01	56.6
2013-04-01	57.2
2013-07-01	57.5
2013-10-01	57.4
2014-01-01	56.9
2014-04-01	57.3
2014-07-01	57.8
2014-10-01	57.6
2015-01-01	57.0
2015-04-01	57.1
2015-07-01	57.6
2015-10-01	57.9
2016-01-01	58.1
2016-04-01	58.1
2016-07-01	58.8
2016-10-01	59.0
2017-01-01	58.3
2017-04-01	58.6
2017-07-01	59.2
2017-10-01	59.5
2018-01-01	58.8
2018-04-01	58.8