Quarter	Percent
2000-04-01	39.7
2001-04-01	40.1
2002-04-01	40.8
2003-04-01	42.7
2004-04-01	43.5
2005-01-01	44.6
2005-04-01	45.2
2005-07-01	45.4
2005-10-01	45.7
2006-01-01	45.6
2006-04-01	46.2
2006-07-01	46.8
2006-10-01	46.7
2007-01-01	46.3
2007-04-01	47.2
2007-07-01	47.3
2007-10-01	47.3
2008-01-01	47.1
2008-04-01	48.0
2008-07-01	48.1
2008-10-01	48.3
2009-01-01	48.4
2009-04-01	49.2
2009-07-01	48.9
2009-10-01	49.1
2010-01-01	49.2
2010-04-01	49.5
2010-07-01	49.8
2010-10-01	49.8
2011-01-01	50.1
2011-04-01	50.6
2011-07-01	50.7
2011-10-01	51.1
2012-01-01	51.4
2012-04-01	52.5
2012-07-01	52.9
2012-10-01	53.2
2013-01-01	53.3
2013-04-01	54.1
2013-07-01	54.7
2013-10-01	55.1
2014-01-01	55.1
2014-04-01	55.7
2014-07-01	56.1
2014-10-01	56.6
2015-01-01	56.4
2015-04-01	57.1
2015-07-01	57.6
2015-10-01	57.9
2016-01-01	58.3
2016-04-01	59.1
2016-07-01	59.3
2016-10-01	59.6
2017-01-01	59.7
2017-04-01	60.6
2017-07-01	60.8
2017-10-01	61.2
2018-01-01	61.3
2018-04-01	61.8