Quarter	Percent
1998-04-01	16.1
1998-10-01	18.0
1999-04-01	17.9
1999-10-01	17.7
2000-04-01	17.3
2000-10-01	16.2
2001-04-01	16.4
2001-10-01	17.7
2002-01-01	20.1
2002-04-01	16.8
2002-07-01	19.4
2002-10-01	15.8
2003-01-01	17.6
2003-04-01	16.8
2003-07-01	16.0
2003-10-01	18.6
2004-01-01	17.2
2004-04-01	18.6
2004-07-01	16.5
2004-10-01	17.3
2005-01-01	18.2
2005-04-01	18.2
2005-07-01	19.5
2005-10-01	18.0
2006-01-01	19.1
2006-04-01	16.7
2006-07-01	18.1
2006-10-01	17.2
2007-01-01	19.3
2007-04-01	18.6
2007-07-01	16.1
2007-10-01	15.0
2008-01-01	15.4
2008-04-01	14.8
2008-07-01	14.4
2008-10-01	13.1
2009-01-01	12.8
2009-04-01	14.5
2009-07-01	15.5
2009-10-01	13.7
2010-01-01	14.8
2010-04-01	13.8
2010-07-01	13.4
2010-10-01	12.7
2011-01-01	14.8
2011-04-01	14.6
2011-07-01	13.6
2011-10-01	15.6
2012-01-01	15.0
2012-04-01	14.3
2012-07-01	13.5
2012-10-01	14.2
2013-01-01	14.5
2013-04-01	15.2
2013-07-01	14.5
2013-10-01	16.6
2014-01-01	15.0
2014-04-01	15.2
2014-07-01	16.1
2014-10-01	17.7
2015-01-01	17.0
2015-04-01	15.4
2015-07-01	13.9
2015-10-01	15.3
2016-01-01	14.7
2016-04-01	15.3
2016-07-01	13.7
2016-10-01	14.2
2017-01-01	15.0
2017-04-01	16.3
2017-07-01	13.7
2017-10-01	13.3
2018-01-01	13.9
2018-04-01	14.3