Quarter	Percent
1998-01-01	14.5
1998-04-01	14
1998-07-01	13.8
1998-10-01	14.6
1999-01-01	15.6
1999-04-01	15.5
1999-07-01	15.3
1999-10-01	16.2
2000-01-01	16.4
2000-04-01	15
2000-07-01	14.5
2000-10-01	14.5
2001-01-01	15.1
2001-04-01	14
2001-07-01	13.7
2001-10-01	15
2002-01-01	15.1
2002-04-01	13.7
2002-07-01	13.6
2002-10-01	14
2003-01-01	14.3
2003-04-01	12.9
2003-07-01	13.1
2003-10-01	14.1
2004-01-01	15.5
2004-04-01	14.4
2004-07-01	14.6
2004-10-01	14.8
2005-01-01	15.1
2005-04-01	14.2
2005-07-01	14.1
2005-10-01	13.9
2006-01-01	13.5
2006-04-01	12.4
2006-07-01	11.9
2006-10-01	12.4
2007-01-01	13.2
2007-04-01	11.9
2007-07-01	11.3
2007-10-01	11.7
2008-01-01	11.7
2008-04-01	10.4
2008-07-01	10.3
2008-10-01	11.1
2009-01-01	12.3
2009-04-01	11.8
2009-07-01	12.3
2009-10-01	13.2
2010-01-01	14.9
2010-04-01	14.5
2010-07-01	15.4
2010-10-01	17.4
2011-01-01	18.9
2011-04-01	19.1
2011-07-01	20.7
2011-10-01	23.8
2012-01-01	25.6
2012-04-01	26.3
2012-07-01	27.8
2012-10-01	28.9
2013-01-01	30.3
2013-04-01	30.6
2013-07-01	31.1
2013-10-01	31.4
2014-01-01	30.9
2014-04-01	29.9
2014-07-01	29
2014-10-01	29.3
2015-01-01	30.4
2015-04-01	28.2
2015-07-01	28.0
2015-10-01	28.2
2016-01-01	29.5
2016-04-01	27.3
2016-07-01	27.3
2016-10-01	28.1
2017-01-01	27.5
2017-04-01	24.9
2017-07-01	24.5
2017-10-01	25.6
2018-01-01	25.9
2018-04-01	23.5