Quarter	Percent
2000-04-01	60.3
2001-04-01	59.9
2002-04-01	59.2
2003-04-01	57.3
2004-04-01	56.5
2005-01-01	55.4
2005-04-01	54.8
2005-07-01	54.6
2005-10-01	54.3
2006-01-01	54.4
2006-04-01	53.8
2006-07-01	53.2
2006-10-01	53.3
2007-01-01	53.7
2007-04-01	52.8
2007-07-01	52.7
2007-10-01	52.7
2008-01-01	52.9
2008-04-01	52.0
2008-07-01	51.9
2008-10-01	51.7
2009-01-01	51.6
2009-04-01	50.8
2009-07-01	51.1
2009-10-01	50.9
2010-01-01	50.8
2010-04-01	50.5
2010-07-01	50.2
2010-10-01	50.2
2011-01-01	49.9
2011-04-01	49.4
2011-07-01	49.3
2011-10-01	48.9
2012-01-01	48.6
2012-04-01	47.5
2012-07-01	47.1
2012-10-01	46.8
2013-01-01	46.7
2013-04-01	45.9
2013-07-01	45.3
2013-10-01	44.9
2014-01-01	44.9
2014-04-01	44.3
2014-07-01	43.9
2014-10-01	43.4
2015-01-01	43.6
2015-04-01	42.9
2015-07-01	42.4
2015-10-01	42.1
2016-01-01	41.7
2016-04-01	40.9
2016-07-01	40.7
2016-10-01	40.4
2017-01-01	40.3
2017-04-01	39.4
2017-07-01	39.2
2017-10-01	38.8
2018-01-01	38.7
2018-04-01	38.2