Quarter	Percent
1999-01-01	48.2
1999-04-01	48
1999-07-01	47.3
1999-10-01	47.3
2000-01-01	47.6
2000-04-01	47.5
2000-07-01	47.1
2000-10-01	46.9
2001-01-01	47.6
2001-04-01	47.9
2001-07-01	47.3
2001-10-01	47.7
2002-01-01	47.7
2002-04-01	47.5
2002-07-01	47
2002-10-01	46.9
2003-01-01	46.6
2003-04-01	46.2
2003-07-01	45.8
2003-10-01	45.7
2004-01-01	46.2
2004-04-01	46.4
2004-07-01	46
2004-10-01	45.5
2005-01-01	45.4
2005-04-01	45
2005-07-01	44.6
2005-10-01	44.7
2006-01-01	44.6
2006-04-01	44.7
2006-07-01	44.3
2006-10-01	44.4
2007-01-01	45.1
2007-04-01	45.3
2007-07-01	44.9
2007-10-01	44.9
2008-01-01	45.6
2008-04-01	45.8
2008-07-01	44.9
2008-10-01	44.8
2009-01-01	45.4
2009-04-01	45.3
2009-07-01	44.9
2009-10-01	44.5
2010-01-01	44.1
2010-04-01	43.9
2010-07-01	43.3
2010-10-01	43.7
2011-01-01	44
2011-04-01	43.5
2011-07-01	43.2
2011-10-01	43
2012-01-01	42.9
2012-04-01	42.1
2012-07-01	41.2
2012-10-01	41.6
2013-01-01	42.2
2013-04-01	41.6
2013-07-01	41.1
2013-10-01	40.8
2014-01-01	40
2014-04-01	39.5
2014-07-01	38.8
2014-10-01	38.8
2015-01-01	38.4
2015-04-01	38.0
2015-07-01	37.3
2015-10-01	37.5
2016-01-01	37.4
2016-04-01	36.8
2016-07-01	36.0
2016-10-01	35.9
2017-01-01	36.4
2017-04-01	35.9
2017-07-01	35.3
2017-10-01	35.4
2018-01-01	35.6
2018-04-01	35.1