Quarter	Percent
1999-04-01	51.1
2000-04-01	52.2
2001-04-01	52.8
2002-04-01	53.3
2003-01-01	52.2
2003-04-01	52.2
2003-07-01	52.2
2003-10-01	52.2
2004-01-01	52.2
2004-04-01	52.2
2004-07-01	52.2
2004-10-01	52.2
2005-01-01	53.1
2005-04-01	53.1
2005-07-01	53.1
2005-10-01	53.1
2006-01-01	52.4
2006-04-01	52.4
2006-07-01	52.4
2006-10-01	52.4
2007-01-01	53.5
2007-04-01	53.2
2007-07-01	54.1
2007-10-01	53.8
2008-01-01	52.8
2008-04-01	54.1
2008-07-01	53.4
2008-10-01	52.3
2009-01-01	54.8
2009-04-01	55.5
2009-07-01	55.6
2009-10-01	54.8
2010-01-01	54.9
2010-04-01	54.6
2010-07-01	55.8
2010-10-01	55.4
2011-01-01	55.5
2011-04-01	54.1
2011-07-01	54.9
2011-10-01	54.6
2012-01-01	54.7
2012-04-01	55.7
2012-07-01	56.3
2012-10-01	56.2
2013-01-01	55.7
2013-04-01	55.5
2013-07-01	56.3
2013-10-01	56.2
2014-01-01	56.6
2014-04-01	56.5
2014-07-01	55.7
2014-10-01	57.4
2015-01-01	56.2
2015-04-01	56.9
2015-07-01	55.3
2015-10-01	55.6
2016-01-01	55.0
2016-04-01	54.9
2016-07-01	54.9
2016-10-01	56.0
2017-01-01	55.8
2017-04-01	55.6
2017-07-01	56.7
2017-10-01	56.1
2018-01-01	56.6
2018-04-01	55.8