Quarter	Percent
1998-04-01	12.1
1999-04-01	12.5
2000-04-01	12.6
2001-04-01	12.1
2002-04-01	11.7
2003-04-01	11.9
2004-04-01	11.8
2005-04-01	11.5
2006-04-01	11.7
2007-04-01	11.1
2008-04-01	10.2
2009-04-01	10
2010-01-01	11.9
2010-04-01	11.6
2010-07-01	11.5
2010-10-01	11.7
2011-01-01	11.0
2011-04-01	11.0
2011-07-01	11.1
2011-10-01	10.8
2012-01-01	10.8
2012-04-01	10.5
2012-07-01	10.4
2012-10-01	10.5
2013-01-01	10.9
2013-04-01	11.0
2013-07-01	10.7
2013-10-01	10.6
2014-01-01	10.5
2014-04-01	10.2
2014-07-01	10.0
2014-10-01	9.6
2015-01-01	9.7
2015-04-01	9.8
2015-07-01	10.1
2015-10-01	9.6
2016-01-01	8.9
2016-04-01	9.6
2016-07-01	9.8
2016-10-01	9.4
2017-01-01	9.4
2017-04-01	9.7
2017-07-01	9.8
2017-10-01	9.6
2018-01-01	9.3
2018-04-01	9.3