Quarter	Percent
1999-01-01	10.6
2000-01-01	14.6
2000-04-01	14.2
2000-07-01	13.2
2000-10-01	13.6
2001-01-01	15.5
2001-04-01	15.9
2001-07-01	15.1
2001-10-01	15.8
2002-01-01	17.6
2002-04-01	17.4
2002-07-01	17
2002-10-01	17
2003-01-01	18
2003-04-01	16.9
2003-07-01	16.6
2003-10-01	16.8
2004-01-01	18.1
2004-04-01	16.8
2004-07-01	16
2004-10-01	15.9
2005-01-01	16.6
2005-04-01	15.9
2005-07-01	15.5
2005-10-01	14.9
2006-01-01	14.4
2006-04-01	12.5
2006-07-01	11.5
2006-10-01	10.5
2007-01-01	9.9
2007-04-01	8.4
2007-07-01	7.8
2007-10-01	7.4
2008-01-01	6.9
2008-04-01	6.2
2008-07-01	5.7
2008-10-01	5.6
2009-01-01	7.1
2009-04-01	6.7
2009-07-01	6.7
2009-10-01	7.1
2010-01-01	9.2
2010-04-01	8.2
2010-07-01	7.7
2010-10-01	8.0
2011-01-01	8.6
2011-04-01	8.1
2011-07-01	7.9
2011-10-01	8.3
2012-01-01	9.1
2012-04-01	8.6
2012-07-01	8.6
2012-10-01	8.8
2013-01-01	9.9
2013-04-01	9.2
2013-07-01	8.6
2013-10-01	8.5
2014-01-01	9.4
2014-04-01	8.1
2014-07-01	7.1
2014-10-01	7.1
2015-01-01	7.6
2015-04-01	6.7
2015-07-01	6.2
2015-10-01	6.0
2016-01-01	6.1
2016-04-01	5.5
2016-07-01	5.1
2016-10-01	4.8
2017-01-01	4.7
2017-04-01	4.3
2017-07-01	4.1
2017-10-01	3.8
2018-01-01	3.6
2018-04-01	3.3