Quarter	Percent
1999-01-01	13.2
2000-01-01	18.6
2000-04-01	18.4
2000-07-01	17.5
2000-10-01	18.1
2001-01-01	19.8
2001-04-01	20.1
2001-07-01	19.7
2001-10-01	20
2002-01-01	21
2002-04-01	20.7
2002-07-01	21.4
2002-10-01	20.6
2003-01-01	20.9
2003-04-01	20
2003-07-01	20.6
2003-10-01	20.4
2004-01-01	21.3
2004-04-01	19.8
2004-07-01	19.2
2004-10-01	19.6
2005-01-01	20.1
2005-04-01	19.2
2005-07-01	19.1
2005-10-01	18.4
2006-01-01	16.8
2006-04-01	14.9
2006-07-01	14.4
2006-10-01	13.8
2007-01-01	12.1
2007-04-01	10.1
2007-07-01	9.8
2007-10-01	9.5
2008-01-01	8.7
2008-04-01	7.8
2008-07-01	7.8
2008-10-01	7.7
2009-01-01	8.9
2009-04-01	8.4
2009-07-01	8.6
2009-10-01	8.8
2010-01-01	10.7
2010-04-01	9.9
2010-07-01	9.8
2010-10-01	9.9
2011-01-01	10.2
2011-04-01	10.1
2011-07-01	10.6
2011-10-01	10.8
2012-01-01	11
2012-04-01	10.7
2012-07-01	10.9
2012-10-01	11.1
2013-01-01	11.9
2013-04-01	11.2
2013-07-01	10.8
2013-10-01	10.5
2014-01-01	11
2014-04-01	9.7
2014-07-01	9.0
2014-10-01	8.7
2015-01-01	8.8
2015-04-01	7.5
2015-07-01	7.5
2015-10-01	7.1
2016-01-01	7.0
2016-04-01	6.0
2016-07-01	6.2
2016-10-01	5.7
2017-01-01	5.4
2017-04-01	4.7
2017-07-01	4.9
2017-10-01	4.6
2018-01-01	4.3
2018-04-01	3.5