Quarter	Percent
1999-01-01	41.8
1999-04-01	41.2
1999-07-01	40.2
1999-10-01	41.1
2000-01-01	40.8
2000-04-01	41
2000-07-01	40.6
2000-10-01	41.4
2001-01-01	41.5
2001-04-01	42.9
2001-07-01	43.2
2001-10-01	45
2002-01-01	46
2002-04-01	45.6
2002-07-01	46.1
2002-10-01	47.4
2003-01-01	46.5
2003-04-01	47.6
2003-07-01	49.2
2003-10-01	49.1
2004-01-01	50.5
2004-04-01	51.1
2004-07-01	52.8
2004-10-01	53.2
2005-01-01	54
2005-04-01	54.2
2005-07-01	55.9
2005-10-01	56.2
2006-01-01	56
2006-04-01	54.5
2006-07-01	55.4
2006-10-01	55
2007-01-01	55.5
2007-04-01	56
2007-07-01	58.6
2007-10-01	57.7
2008-01-01	58.5
2008-04-01	59.4
2008-07-01	61
2008-10-01	60.5
2009-01-01	58.7
2009-04-01	58.1
2009-07-01	59
2009-10-01	58.9
2010-01-01	59.8
2010-04-01	60.5
2010-07-01	59.6
2010-10-01	59
2011-01-01	58.3
2011-04-01	58.9
2011-07-01	59.1
2011-10-01	58.8
2012-01-01	58.9
2012-04-01	60.5
2012-07-01	60
2012-10-01	61.6
2013-01-01	59.9
2013-04-01	60.3
2013-07-01	59.8
2013-10-01	58.2
2014-01-01	58.4
2014-04-01	58.9
2014-07-01	59.2
2014-10-01	58.9
2015-01-01	58.2
2015-04-01	57.8
2015-07-01	58.4
2015-10-01	59.1
2016-01-01	59.3
2016-04-01	61.6
2016-07-01	59.5
2016-10-01	60.1
2017-01-01	59.4
2017-04-01	59.9
2017-07-01	60.2
2017-10-01	60.5
2018-01-01	61.0
2018-04-01	60.4