Quarter	Percent
1998-01-01	12.4
1998-04-01	12.7
1998-07-01	16.4
1998-10-01	17.0
1999-01-01	16.6
1999-04-01	16.9
1999-07-01	21
1999-10-01	19.1
2000-01-01	17.1
2000-04-01	16.4
2000-07-01	18.2
2000-10-01	17.5
2001-01-01	17
2001-04-01	16.2
2001-07-01	18.4
2001-10-01	17.3
2002-01-01	16.2
2002-04-01	15
2002-07-01	19
2002-10-01	18.6
2003-01-01	19.6
2003-04-01	17.5
2003-07-01	19.2
2003-10-01	19
2004-01-01	18.9
2004-04-01	17.9
2004-07-01	20.6
2004-10-01	20.6
2005-01-01	17.4
2005-04-01	18.3
2005-07-01	20.2
2005-10-01	20.1
2006-01-01	20.5
2006-04-01	18.3
2006-07-01	19.1
2006-10-01	16.8
2007-01-01	11.9
2007-04-01	9.8
2007-07-01	11.6
2007-10-01	10.5
2008-01-01	9.7
2008-04-01	7.7
2008-07-01	11.2
2008-10-01	11
2009-01-01	13.5
2009-04-01	14.5
2009-07-01	17.9
2009-10-01	20.7
2010-01-01	18.7
2010-04-01	17.7
2010-07-01	19.5
2010-10-01	18
2011-01-01	17.5
2011-04-01	18.9
2011-07-01	17.9
2011-10-01	17.6
2012-01-01	18.1
2012-04-01	18.4
2012-07-01	19.4
2012-10-01	20.1
2013-01-01	18
2013-04-01	19
2013-07-01	20.6
2013-10-01	20.2
2014-01-01	17.4
2014-04-01	18.2
2014-07-01	18
2014-10-01	14.9
2015-01-01	13.5
2015-04-01	13.9
2015-07-01	16.0
2015-10-01	14.3
2016-01-01	10.8
2016-04-01	10.0
2016-07-01	13.2
2016-10-01	11.5
2017-01-01	9.8
2017-04-01	10.3
2017-07-01	8.7
2017-10-01	6.2
2018-01-01	6.5
2018-04-01	8.4