Quarter	Percent
1999-04-01	15.2
2000-04-01	14.2
2001-04-01	12.8
2002-04-01	12.1
2003-04-01	12.9
2004-04-01	12.7
2005-01-01	12.5
2005-04-01	12.9
2005-07-01	13.2
2005-10-01	13.3
2006-01-01	13.8
2006-04-01	13.1
2006-07-01	12.5
2006-10-01	12.5
2007-01-01	12.2
2007-04-01	10.6
2007-07-01	10.8
2007-10-01	11.2
2008-01-01	9.1
2008-04-01	9.3
2008-07-01	8.7
2008-10-01	8.6
2009-01-01	8.5
2009-04-01	7.7
2009-07-01	7.8
2009-10-01	8.1
2010-01-01	7.6
2010-04-01	6.9
2010-07-01	6.6
2010-10-01	7.5
2011-01-01	7.2
2011-04-01	6.3
2011-07-01	5.9
2011-10-01	5.9
2012-01-01	5.4
2012-04-01	5.7
2012-07-01	5.2
2012-10-01	5.8
2013-01-01	5.9
2013-04-01	5.2
2013-07-01	4.9
2013-10-01	4.9
2014-01-01	5.2
2014-04-01	4.6
2014-07-01	4.4
2014-10-01	4.5
2015-01-01	4.8
2015-04-01	3.9
2015-07-01	3.8
2015-10-01	4.1
2016-01-01	3.8
2016-04-01	3.7
2016-07-01	3.4
2016-10-01	3.4
2017-01-01	3.3
2017-04-01	3.1
2017-07-01	3.0
2017-10-01	2.9
2018-01-01	2.7
2018-04-01	2.8