Quarter	Percent
2000-04-01	62.7
2001-04-01	62.6
2002-04-01	61.1
2003-04-01	59.4
2004-04-01	58.4
2005-01-01	56.8
2005-04-01	56.2
2005-07-01	56.3
2005-10-01	55.7
2006-01-01	55.6
2006-04-01	55.2
2006-07-01	55
2006-10-01	54.5
2007-01-01	54.4
2007-04-01	53.6
2007-07-01	53.8
2007-10-01	53.6
2008-01-01	53.7
2008-04-01	52.8
2008-07-01	52.7
2008-10-01	52.4
2009-01-01	52.1
2009-04-01	51.1
2009-07-01	51.7
2009-10-01	51.2
2010-01-01	50.9
2010-04-01	50.7
2010-07-01	50.6
2010-10-01	50.3
2011-01-01	50.1
2011-04-01	49.3
2011-07-01	49.3
2011-10-01	48.6
2012-01-01	48.3
2012-04-01	47.3
2012-07-01	46.9
2012-10-01	46.5
2013-01-01	46.3
2013-04-01	45.6
2013-07-01	45
2013-10-01	44.6
2014-01-01	44.4
2014-04-01	43.8
2014-07-01	43.4
2014-10-01	42.8
2015-01-01	42.7
2015-04-01	42.0
2015-07-01	41.8
2015-10-01	41.5
2016-01-01	40.9
2016-04-01	40.2
2016-07-01	40.0
2016-10-01	39.7
2017-01-01	39.6
2017-04-01	38.7
2017-07-01	38.6
2017-10-01	38.0
2018-01-01	37.9
2018-04-01	37.5