Quarter	Percent
1998-04-01	16
1999-04-01	14.8
2000-04-01	15.1
2001-01-01	14.8
2001-04-01	14.6
2001-07-01	14
2001-10-01	14.6
2002-01-01	14.7
2002-04-01	14.3
2002-07-01	14
2002-10-01	15
2003-01-01	14.8
2003-04-01	14.3
2003-07-01	14.3
2003-10-01	14.9
2004-01-01	15.1
2004-04-01	14.4
2004-07-01	14.1
2004-10-01	15.4
2005-01-01	15.7
2005-04-01	13.5
2005-07-01	13.5
2005-10-01	13.8
2006-01-01	14.2
2006-04-01	13.6
2006-07-01	13.2
2006-10-01	14
2007-01-01	13.6
2007-04-01	12.7
2007-07-01	12.6
2007-10-01	12.8
2008-01-01	12.8
2008-04-01	12.2
2008-07-01	12
2008-10-01	12.7
2009-01-01	12.9
2009-04-01	12.5
2009-07-01	12.5
2009-10-01	13.5
2010-01-01	14
2010-04-01	13
2010-07-01	12.9
2010-10-01	13.6
2011-01-01	13.2
2011-04-01	12.3
2011-07-01	12.5
2011-10-01	12.7
2012-01-01	12.9
2012-04-01	12.1
2012-07-01	12.1
2012-10-01	12.6
2013-01-01	12.4
2013-04-01	11.5
2013-07-01	11.5
2013-10-01	12.1
2014-01-01	12.4
2014-04-01	11.8
2014-07-01	11.5
2014-10-01	12.4
2015-01-01	12.2
2015-04-01	11.3
2015-07-01	11.5
2015-10-01	11.5
2016-01-01	12.0
2016-04-01	11.4
2016-07-01	11.2
2016-10-01	11.6
2017-01-01	11.5
2017-04-01	11.1
2017-07-01	10.8
2017-10-01	11.6
2018-01-01	11.5
2018-04-01	10.4