Quarter	Percent
1999-01-01	13.4
1999-04-01	12.3
1999-07-01	13.7
1999-10-01	11.7
2000-01-01	12.4
2000-04-01	12.3
2000-07-01	13
2000-10-01	12.2
2001-01-01	11.7
2001-04-01	10.7
2001-07-01	11.5
2001-10-01	11.3
2002-01-01	11.8
2002-04-01	11.4
2002-07-01	14.2
2002-10-01	13.2
2003-01-01	14.4
2003-04-01	12.9
2003-07-01	13.5
2003-10-01	12.6
2004-01-01	14.1
2004-04-01	14.4
2004-07-01	16.6
2004-10-01	16.8
2005-01-01	18.8
2005-04-01	19.2
2005-07-01	20.5
2005-10-01	19.1
2006-01-01	18.9
2006-04-01	17.4
2006-07-01	20.5
2006-10-01	19.7
2007-01-01	18.5
2007-04-01	16.2
2007-07-01	18.3
2007-10-01	19
2008-01-01	19.6
2008-04-01	18.6
2008-07-01	20.4
2008-10-01	19.4
2009-01-01	25
2009-04-01	25.1
2009-07-01	27.5
2009-10-01	27.9
2010-01-01	27.5
2010-04-01	26.6
2010-07-01	26.5
2010-10-01	25.1
2011-01-01	26.7
2011-04-01	24.1
2011-07-01	26.3
2011-10-01	26.7
2012-01-01	28.4
2012-04-01	28.2
2012-07-01	29.1
2012-10-01	27.2
2013-01-01	29.8
2013-04-01	25.7
2013-07-01	26.8
2013-10-01	24.1
2014-01-01	21
2014-04-01	20.7
2014-07-01	21.6
2014-10-01	18.3
2015-01-01	19.4
2015-04-01	17.8
2015-07-01	16.7
2015-10-01	15.3
2016-01-01	14.2
2016-04-01	13.3
2016-07-01	12.7
2016-10-01	11.6
2017-01-01	10.3
2017-04-01	11.0
2017-07-01	11.3
2017-10-01	10.2
2018-01-01	10.4
2018-04-01	9.5