Quarter	Percent
1999-04-01	14.2
2000-04-01	12.7
2001-04-01	12
2002-04-01	11.2
2003-04-01	12.6
2004-04-01	12.8
2005-01-01	12.4
2005-04-01	13.1
2005-07-01	12.8
2005-10-01	12.7
2006-01-01	13.5
2006-04-01	12.2
2006-07-01	11.6
2006-10-01	12.1
2007-01-01	11.5
2007-04-01	10.1
2007-07-01	9.8
2007-10-01	10
2008-01-01	9.1
2008-04-01	8.8
2008-07-01	8.0
2008-10-01	8.0
2009-01-01	8.7
2009-04-01	7.6
2009-07-01	7.9
2009-10-01	7.9
2010-01-01	8.1
2010-04-01	7.7
2010-07-01	7.1
2010-10-01	7.5
2011-01-01	7.5
2011-04-01	6.5
2011-07-01	5.9
2011-10-01	5.7
2012-01-01	6.2
2012-04-01	5.9
2012-07-01	5.6
2012-10-01	5.7
2013-01-01	6.4
2013-04-01	5.7
2013-07-01	5.3
2013-10-01	5.4
2014-01-01	5.7
2014-04-01	5.1
2014-07-01	4.7
2014-10-01	5.0
2015-01-01	5.4
2015-04-01	4.7
2015-07-01	4.2
2015-10-01	4.5
2016-01-01	4.1
2016-04-01	3.9
2016-07-01	3.7
2016-10-01	3.7
2017-01-01	3.7
2017-04-01	3.4
2017-07-01	3.3
2017-10-01	3.2
2018-01-01	3.2
2018-04-01	3.0