Quarter	Percent
1999-04-01	56
2000-04-01	54.7
2001-04-01	54
2002-04-01	52.6
2003-01-01	52.8
2003-04-01	52.8
2003-07-01	52.8
2003-10-01	52.8
2004-01-01	51
2004-04-01	51
2004-07-01	51
2004-10-01	51
2005-01-01	50
2005-04-01	50
2005-07-01	50
2005-10-01	50
2006-01-01	47.6
2006-04-01	47.6
2006-07-01	47.6
2006-10-01	47.6
2007-01-01	46.7
2007-04-01	49.1
2007-07-01	46
2007-10-01	45.1
2008-01-01	48.4
2008-04-01	47
2008-07-01	48.5
2008-10-01	48.9
2009-01-01	45.7
2009-04-01	46.8
2009-07-01	47
2009-10-01	47.2
2010-01-01	46.9
2010-04-01	47.5
2010-07-01	46.3
2010-10-01	46.3
2011-01-01	45.2
2011-04-01	47.4
2011-07-01	46.8
2011-10-01	47.1
2012-01-01	45.4
2012-04-01	45.7
2012-07-01	43
2012-10-01	44.5
2013-01-01	44.1
2013-04-01	43.9
2013-07-01	44.6
2013-10-01	44.1
2014-01-01	43.4
2014-04-01	43.5
2014-07-01	43.1
2014-10-01	42
2015-01-01	39.3
2015-04-01	39.9
2015-07-01	40.6
2015-10-01	41.1
2016-01-01	41.7
2016-04-01	42.0
2016-07-01	40.7
2016-10-01	40.5
2017-01-01	41.4
2017-04-01	41.3
2017-07-01	38.3
2017-10-01	40.3
2018-01-01	38.6
2018-04-01	39.9