Quarter	Percent
1998-01-01	16.4
1998-04-01	16.6
1998-07-01	15.8
1998-10-01	16.5
1999-01-01	16.3
1999-04-01	16.3
1999-07-01	15.2
1999-10-01	15.2
2000-01-01	15.3
2000-04-01	14.9
2000-07-01	14.1
2000-10-01	13.8
2001-01-01	13.7
2001-04-01	13.1
2001-07-01	12.5
2001-10-01	12.7
2002-01-01	12.5
2002-04-01	12.6
2002-07-01	11.7
2002-10-01	12.1
2003-01-01	11.9
2003-04-01	12
2003-07-01	11.3
2003-10-01	11.4
2004-01-01	11.4
2004-04-01	10.2
2004-07-01	9.8
2004-10-01	10.5
2005-01-01	10.4
2005-04-01	9.7
2005-07-01	9.4
2005-10-01	10.7
2006-01-01	9.9
2006-04-01	8.5
2006-07-01	7.9
2006-10-01	8.8
2007-01-01	8.0
2007-04-01	7.4
2007-07-01	7.4
2007-10-01	8.6
2008-01-01	9.0
2008-04-01	8.7
2008-07-01	7.9
2008-10-01	8.5
2009-01-01	9.5
2009-04-01	8.8
2009-07-01	8.5
2009-10-01	10.1
2010-01-01	10.5
2010-04-01	9.4
2010-07-01	8.6
2010-10-01	9.9
2011-01-01	9.6
2011-04-01	8.9
2011-07-01	8.9
2011-10-01	10.8
2012-01-01	12.1
2012-04-01	11.4
2012-07-01	11
2012-10-01	12.8
2013-01-01	13.8
2013-04-01	12.7
2013-07-01	12
2013-10-01	13.7
2014-01-01	14.4
2014-04-01	13.3
2014-07-01	12.8
2014-10-01	14.7
2015-01-01	13.8
2015-04-01	12.8
2015-07-01	11.4
2015-10-01	12.8
2016-01-01	12.9
2016-04-01	12.8
2016-07-01	12.0
2016-10-01	13.4
2017-01-01	13.3
2017-04-01	12.1
2017-07-01	11.8
2017-10-01	12.3
2018-01-01	12.9
2018-04-01	11.8