Quarter	Percent
1998-01-01	11.9
1998-04-01	10.9
1998-07-01	10.8
1998-10-01	11.4
1999-01-01	12.2
1999-04-01	11.9
1999-07-01	11.7
1999-10-01	12.7
2000-01-01	12.3
2000-04-01	11.3
2000-07-01	10.9
2000-10-01	11
2001-01-01	11.2
2001-04-01	10.5
2001-07-01	10.2
2001-10-01	11.3
2002-01-01	11.4
2002-04-01	10
2002-07-01	9.9
2002-10-01	10.2
2003-01-01	10.5
2003-04-01	9.4
2003-07-01	9.3
2003-10-01	10
2004-01-01	11.4
2004-04-01	10.3
2004-07-01	10.2
2004-10-01	10.5
2005-01-01	10.5
2005-04-01	9.8
2005-07-01	9.9
2005-10-01	9.9
2006-01-01	9.8
2006-04-01	8.9
2006-07-01	8.5
2006-10-01	8.9
2007-01-01	9.3
2007-04-01	8.2
2007-07-01	8.0
2007-10-01	8.2
2008-01-01	8.4
2008-04-01	7.3
2008-07-01	7.3
2008-10-01	8.1
2009-01-01	9.5
2009-04-01	9.1
2009-07-01	9.5
2009-10-01	10.5
2010-01-01	11.9
2010-04-01	12
2010-07-01	12.6
2010-10-01	14.5
2011-01-01	16.1
2011-04-01	16.5
2011-07-01	18
2011-10-01	21
2012-01-01	22.9
2012-04-01	23.8
2012-07-01	25
2012-10-01	26.3
2013-01-01	27.6
2013-04-01	27.3
2013-07-01	27.2
2013-10-01	27.8
2014-01-01	27.9
2014-04-01	26.6
2014-07-01	25.6
2014-10-01	26.1
2015-01-01	26.7
2015-04-01	24.6
2015-07-01	24.1
2015-10-01	24.4
2016-01-01	24.9
2016-04-01	23.1
2016-07-01	22.6
2016-10-01	23.6
2017-01-01	23.4
2017-04-01	21.2
2017-07-01	20.3
2017-10-01	21.2
2018-01-01	21.2
2018-04-01	19.0