Quarter	Percent
1998-01-01	19.5
1998-04-01	20.4
1998-07-01	21.7
1998-10-01	21.1
1999-01-01	20.4
1999-04-01	20.8
1999-07-01	22.6
1999-10-01	21.3
2000-01-01	21.1
2000-04-01	22
2000-07-01	22.9
2000-10-01	22.7
2001-01-01	21.9
2001-04-01	22.2
2001-07-01	22.2
2001-10-01	22.2
2002-01-01	21.2
2002-04-01	21.1
2002-07-01	21.7
2002-10-01	20.9
2003-01-01	20.5
2003-04-01	20.8
2003-07-01	21.7
2003-10-01	19.6
2004-01-01	23
2004-04-01	22.7
2004-07-01	24.4
2004-10-01	22.3
2005-01-01	20.6
2005-04-01	20.9
2005-07-01	20.4
2005-10-01	21.3
2006-01-01	20.5
2006-04-01	19.6
2006-07-01	20.3
2006-10-01	19.7
2007-01-01	19
2007-04-01	19.8
2007-07-01	20.1
2007-10-01	19.1
2008-01-01	19.5
2008-04-01	19.1
2008-07-01	19.9
2008-10-01	18.3
2009-01-01	17
2009-04-01	17.1
2009-07-01	17
2009-10-01	16.5
2010-01-01	16.3
2010-04-01	16.4
2010-07-01	16.5
2010-10-01	16.1
2011-01-01	15.2
2011-04-01	14.8
2011-07-01	15.9
2011-10-01	16
2012-01-01	14.7
2012-04-01	15.1
2012-07-01	15.7
2012-10-01	14.5
2013-01-01	13.6
2013-04-01	14.3
2013-07-01	14.4
2013-10-01	12.6
2014-01-01	11.8
2014-04-01	13.4
2014-07-01	13.6
2014-10-01	12.2
2015-01-01	11.2
2015-04-01	12.3
2015-07-01	13.2
2015-10-01	13.1
2016-01-01	13.0
2016-04-01	14.7
2016-07-01	14.2
2016-10-01	13.0
2017-01-01	13.4
2017-04-01	14.2
2017-07-01	14.5
2017-10-01	13.4
2018-01-01	13.9
2018-04-01	14.3