Quarter	Percent
1998-01-01	3.7
1998-04-01	3.2
1998-07-01	2.9
1998-10-01	3.7
1999-01-01	4.3
1999-04-01	4.3
1999-07-01	3.5
1999-10-01	3.8
2000-01-01	4.0
2000-04-01	3.7
2000-07-01	3.7
2000-10-01	4.0
2001-01-01	4.3
2001-04-01	4.1
2001-07-01	3.9
2001-10-01	4.6
2002-01-01	5.0
2002-04-01	3.8
2002-07-01	3.8
2002-10-01	3.9
2003-01-01	3.7
2003-04-01	3.1
2003-07-01	2.8
2003-10-01	3.1
2004-01-01	5.0
2004-04-01	4.2
2004-07-01	4.0
2004-10-01	4.5
2005-01-01	4.6
2005-04-01	3.4
2005-07-01	3.5
2005-10-01	3.6
2006-01-01	4.5
2006-04-01	3.5
2006-07-01	3.2
2006-10-01	3.6
2007-01-01	4.0
2007-04-01	3.4
2007-07-01	3.1
2007-10-01	3.1
2008-01-01	3.4
2008-04-01	3.1
2008-07-01	3.0
2008-10-01	3.4
2009-01-01	4.1
2009-04-01	4.3
2009-07-01	4.7
2009-10-01	5.1
2010-01-01	6.1
2010-04-01	6.1
2010-07-01	5.8
2010-10-01	6.9
2011-01-01	7.7
2011-04-01	7.7
2011-07-01	8.3
2011-10-01	10
2012-01-01	11.8
2012-04-01	13
2012-07-01	13.9
2012-10-01	15.1
2013-01-01	16.5
2013-04-01	15.8
2013-07-01	15.6
2013-10-01	17
2014-01-01	17.9
2014-04-01	17.9
2014-07-01	16.3
2014-10-01	16.6
2015-01-01	18.6
2015-04-01	17.0
2015-07-01	16.7
2015-10-01	17.8
2016-01-01	19.5
2016-04-01	19.3
2016-07-01	18.3
2016-10-01	19.6
2017-01-01	19.3
2017-04-01	18.1
2017-07-01	17.9
2017-10-01	17.3
2018-01-01	16.6
2018-04-01	15.6