Quarter	Percent
1999-01-01	46.7
2000-01-01	47.9
2001-01-01	48.7
2002-01-01	49.4
2003-01-01	51.1
2003-04-01	51.2
2003-07-01	51.5
2003-10-01	50.6
2004-01-01	50.6
2004-04-01	51.3
2004-07-01	51.7
2004-10-01	51.1
2005-01-01	51.4
2005-04-01	51.8
2005-07-01	51.8
2005-10-01	51.0
2006-01-01	51.2
2006-04-01	51.6
2006-07-01	52.1
2006-10-01	52.3
2007-01-01	52.1
2007-04-01	52.8
2007-07-01	53.3
2007-10-01	53.2
2008-01-01	53.4
2008-04-01	53.7
2008-07-01	53.9
2008-10-01	53.3
2009-01-01	53
2009-04-01	53.5
2009-07-01	53.5
2009-10-01	52.8
2010-01-01	53.0
2010-04-01	53.4
2010-07-01	53.6
2010-10-01	52.7
2011-01-01	52.6
2011-04-01	53.2
2011-07-01	53.3
2011-10-01	53
2012-01-01	52.9
2012-04-01	53.3
2012-07-01	53.4
2012-10-01	52.9
2013-01-01	52.7
2013-04-01	53.2
2013-07-01	53.5
2013-10-01	53.1
2014-01-01	52.8
2014-04-01	53.1
2014-07-01	52.9
2014-10-01	52.6
2015-01-01	52.5
2015-04-01	53.0
2015-07-01	53.2
2015-10-01	52.7
2016-01-01	52.7
2016-04-01	53.0
2016-07-01	52.9
2016-10-01	52.5
2017-01-01	52.3
2017-04-01	53.2
2017-07-01	52.8
2017-10-01	53.0
2018-01-01	52.7
2018-04-01	53.3