Quarter	Percent
1999-01-01	12.9
1999-04-01	13.1
1999-07-01	13.4
1999-10-01	14.3
2000-01-01	15.3
2000-04-01	16
2000-07-01	16.2
2000-10-01	15.6
2001-01-01	16
2001-04-01	15.9
2001-07-01	15.6
2001-10-01	15.6
2002-01-01	16.5
2002-04-01	15.8
2002-07-01	15.6
2002-10-01	15.4
2003-01-01	15.6
2003-04-01	15.3
2003-07-01	15.4
2003-10-01	16.4
2004-01-01	18.2
2004-04-01	18.1
2004-07-01	17.2
2004-10-01	16.7
2005-01-01	16.7
2005-04-01	16
2005-07-01	15.3
2005-10-01	15.2
2006-01-01	14.9
2006-04-01	14
2006-07-01	12.8
2006-10-01	12.4
2007-01-01	12.1
2007-04-01	12.4
2007-07-01	12.1
2007-10-01	11.5
2008-01-01	11.5
2008-04-01	10.9
2008-07-01	9.5
2008-10-01	9.0
2009-01-01	10.5
2009-04-01	11.6
2009-07-01	12
2009-10-01	12.9
2010-01-01	14.3
2010-04-01	13.6
2010-07-01	12.9
2010-10-01	12.5
2011-01-01	12.8
2011-04-01	11.9
2011-07-01	12.2
2011-10-01	13.2
2012-01-01	13.6
2012-04-01	13.1
2012-07-01	13.2
2012-10-01	13.8
2013-01-01	14.6
2013-04-01	13.5
2013-07-01	13.4
2013-10-01	12.9
2014-01-01	12.6
2014-04-01	12.3
2014-07-01	12.8
2014-10-01	13
2015-01-01	12.5
2015-04-01	12.3
2015-07-01	12.2
2015-10-01	11.7
2016-01-01	10.6
2016-04-01	9.9
2016-07-01	9.7
2016-10-01	9.0
2017-01-01	8.4
2017-04-01	7.9
2017-07-01	7.7
2017-10-01	7.7
2018-01-01	7.0
2018-04-01	6.9