Quarter	Percent
1999-04-01	46.8
1999-07-01	58.4
1999-10-01	49.3
2000-01-01	47.3
2000-04-01	46.7
2000-07-01	57.5
2000-10-01	48.8
2001-01-01	46.8
2001-04-01	44.8
2001-07-01	55.9
2001-10-01	47.6
2002-01-01	46.7
2002-04-01	44.6
2002-07-01	54.2
2002-10-01	47.1
2003-01-01	45.6
2003-04-01	45.5
2003-07-01	54.6
2003-10-01	48.1
2004-01-01	46.6
2004-04-01	44.7
2004-07-01	54.2
2004-10-01	49.8
2005-01-01	47.3
2005-04-01	47.6
2005-07-01	55.2
2005-10-01	49.4
2006-01-01	47.6
2006-04-01	48.2
2006-07-01	56.6
2006-10-01	49.9
2007-01-01	61.1
2007-04-01	64.4
2007-07-01	68.3
2007-10-01	62.9
2008-01-01	60.4
2008-04-01	62.7
2008-07-01	65.9
2008-10-01	58.4
2009-01-01	56.9
2009-04-01	59.4
2009-07-01	58.8
2009-10-01	54.4
2010-01-01	48.9
2010-04-01	52.5
2010-07-01	53.5
2010-10-01	52.0
2011-01-01	48.3
2011-04-01	50.3
2011-07-01	50.0
2011-10-01	47.9
2012-01-01	46.8
2012-04-01	50.0
2012-07-01	51.1
2012-10-01	46.7
2013-01-01	45.0
2013-04-01	50.1
2013-07-01	51.5
2013-10-01	45.9
2014-01-01	42.8
2014-04-01	45.0
2014-07-01	50.1
2014-10-01	45.4
2015-01-01	41.9
2015-04-01	44.0
2015-07-01	48.2
2015-10-01	44.2
2016-01-01	41.9
2016-04-01	51.0
2016-07-01	52.2
2016-10-01	48.5
2017-01-01	45.2
2017-04-01	48.1
2017-07-01	45.2
2017-10-01	43.5
2018-01-01	40.7
2018-04-01	45.8