Quarter	Percent
1999-04-01	41.1
1999-07-01	40.7
1999-10-01	41.5
2000-01-01	42.2
2000-04-01	42.6
2000-07-01	43.1
2000-10-01	43.5
2001-01-01	43.7
2001-04-01	43.9
2001-07-01	43.9
2001-10-01	44.4
2002-01-01	44.8
2002-04-01	45.6
2002-07-01	45.7
2002-10-01	46.3
2003-01-01	46.4
2003-04-01	47.2
2003-07-01	47.6
2003-10-01	47.7
2004-01-01	47.6
2004-04-01	48.2
2004-07-01	47.4
2004-10-01	48.2
2005-01-01	48.7
2005-04-01	49
2005-07-01	48.8
2005-10-01	49
2006-01-01	49.6
2006-04-01	50.1
2006-07-01	50.4
2006-10-01	50.5
2007-01-01	50.2
2007-04-01	49.9
2007-07-01	49.6
2007-10-01	50.1
2008-01-01	50
2008-04-01	50
2008-07-01	50.0
2008-10-01	50.8
2009-01-01	50.6
2009-04-01	50.8
2009-07-01	50.5
2009-10-01	50.7
2010-01-01	51.3
2010-04-01	50.6
2010-07-01	51.7
2010-10-01	50.9
2011-01-01	51.2
2011-04-01	51
2011-07-01	51.6
2011-10-01	51.3
2012-01-01	52.4
2012-04-01	53
2012-07-01	52.7
2012-10-01	53.8
2013-01-01	54.5
2013-04-01	55.1
2013-07-01	55.5
2013-10-01	56.0
2014-01-01	56.3
2014-04-01	56.4
2014-07-01	56.0
2014-10-01	56.9
2015-01-01	57.4
2015-04-01	57.1
2015-07-01	58.0
2015-10-01	58.3
2016-01-01	58.9
2016-04-01	59.7
2016-07-01	58.9
2016-10-01	59.5
2017-01-01	60.3
2017-04-01	60.4
2017-07-01	61.1
2017-10-01	61.8
2018-01-01	62.3
2018-04-01	62.3