Quarter	Percent
1999-01-01	52.4
2000-01-01	49.7
2000-04-01	50.3
2000-07-01	50.6
2000-10-01	49.9
2001-01-01	48.7
2001-04-01	49
2001-07-01	49.2
2001-10-01	48.1
2002-01-01	46.8
2002-04-01	47.2
2002-07-01	47.3
2002-10-01	46.8
2003-01-01	45.9
2003-04-01	46.7
2003-07-01	47.1
2003-10-01	46.9
2004-01-01	46
2004-04-01	46.8
2004-07-01	47.7
2004-10-01	47.9
2005-01-01	46.9
2005-04-01	47.7
2005-07-01	49.2
2005-10-01	49
2006-01-01	47.9
2006-04-01	49.3
2006-07-01	50.8
2006-10-01	50.7
2007-01-01	50.4
2007-04-01	51.9
2007-07-01	52.8
2007-10-01	53
2008-01-01	53
2008-04-01	53.9
2008-07-01	54.9
2008-10-01	54.9
2009-01-01	53.9
2009-04-01	54.3
2009-07-01	54.9
2009-10-01	54.4
2010-01-01	52.9
2010-04-01	54
2010-07-01	54.7
2010-10-01	54.2
2011-01-01	53.5
2011-04-01	54.3
2011-07-01	54.7
2011-10-01	54.4
2012-01-01	53.7
2012-04-01	54.5
2012-07-01	54.8
2012-10-01	54.6
2013-01-01	53.4
2013-04-01	54.2
2013-07-01	55.1
2013-10-01	55
2014-01-01	54.5
2014-04-01	55.3
2014-07-01	56.4
2014-10-01	56.3
2015-01-01	55.6
2015-04-01	56.1
2015-07-01	57.1
2015-10-01	57.2
2016-01-01	56.9
2016-04-01	57.5
2016-07-01	57.8
2016-10-01	58.0
2017-01-01	58.1
2017-04-01	58.7
2017-07-01	58.9
2017-10-01	58.6
2018-01-01	58.5
2018-04-01	59.4