Quarter	Percent
1999-01-01	61.2
1999-04-01	61.3
1999-07-01	61.2
1999-10-01	61.1
2000-01-01	60.3
2000-04-01	59.2
2000-07-01	58.8
2000-10-01	58.2
2001-01-01	58.5
2001-04-01	58.3
2001-07-01	58
2001-10-01	57.6
2002-01-01	57.5
2002-04-01	57
2002-07-01	57
2002-10-01	56.4
2003-01-01	56.4
2003-04-01	56.1
2003-07-01	55.9
2003-10-01	55.6
2004-01-01	55.6
2004-04-01	55.7
2004-07-01	55.6
2004-10-01	55.3
2005-01-01	54.5
2005-04-01	53.8
2005-07-01	54.5
2005-10-01	53.3
2006-01-01	52.8
2006-04-01	53.1
2006-07-01	53.7
2006-10-01	53.1
2007-01-01	53.1
2007-04-01	52.6
2007-07-01	52.8
2007-10-01	52.2
2008-01-01	51.5
2008-04-01	50.9
2008-07-01	51
2008-10-01	50.2
2009-01-01	50
2009-04-01	49.4
2009-07-01	50.4
2009-10-01	50.1
2010-01-01	49.8
2010-04-01	49.5
2010-07-01	49
2010-10-01	48.7
2011-01-01	48.4
2011-04-01	47.6
2011-07-01	47.4
2011-10-01	47
2012-01-01	47.2
2012-04-01	46.2
2012-07-01	46.1
2012-10-01	46.5
2013-01-01	46.4
2013-04-01	46.2
2013-07-01	45.7
2013-10-01	45.5
2014-01-01	45.5
2014-04-01	44.8
2014-07-01	44.6
2014-10-01	43.5
2015-01-01	43.3
2015-04-01	42.6
2015-07-01	42.4
2015-10-01	41.2
2016-01-01	40.8
2016-04-01	41.1
2016-07-01	40.6
2016-10-01	40.7
2017-01-01	40.7
2017-04-01	40.3
2017-07-01	40.4
2017-10-01	40.1
2018-01-01	39.9
2018-04-01	39.5
2018-07-01	39.7