Quarter	Percent
1998-01-01	9.5
1998-04-01	8.5
1998-07-01	7.8
1998-10-01	8.5
1999-01-01	8.7
1999-04-01	7.7
1999-07-01	6.7
1999-10-01	6.6
2000-01-01	7.9
2000-04-01	5.5
2000-07-01	6.7
2000-10-01	6.3
2001-01-01	6.3
2001-04-01	6.5
2001-07-01	7.7
2001-10-01	8.5
2002-01-01	9.1
2002-04-01	9.2
2002-07-01	10.8
2002-10-01	10.3
2003-01-01	11.4
2003-04-01	10.8
2003-07-01	13.3
2003-10-01	14.7
2004-01-01	14.2
2004-04-01	12.6
2004-07-01	13.9
2004-10-01	13.8
2005-01-01	13.2
2005-04-01	13.8
2005-07-01	13.7
2005-10-01	14.9
2006-01-01	14.4
2006-04-01	14.4
2006-07-01	15.1
2006-10-01	15.8
2007-01-01	16.4
2007-04-01	12.4
2007-07-01	13.1
2007-10-01	13.3
2008-01-01	13.5
2008-04-01	11.9
2008-07-01	13.7
2008-10-01	15.4
2009-01-01	18.9
2009-04-01	19.2
2009-07-01	16.7
2009-10-01	21.4
2010-01-01	22.7
2010-04-01	21.2
2010-07-01	22.1
2010-10-01	20.5
2011-01-01	26.6
2011-04-01	27.3
2011-07-01	28.2
2011-10-01	33.9
2012-01-01	35.9
2012-04-01	35.1
2012-07-01	37.7
2012-10-01	38.3
2013-01-01	40.1
2013-04-01	35.1
2013-07-01	37.3
2013-10-01	34.2
2014-01-01	37.1
2014-04-01	36.5
2014-07-01	30
2014-10-01	33.4
2015-01-01	30.1
2015-04-01	28.1
2015-07-01	28.1
2015-10-01	32.0
2016-01-01	30.1
2016-04-01	25.8
2016-07-01	25.3
2016-10-01	27.9
2017-01-01	24.0
2017-04-01	22.8
2017-07-01	21.6
2017-10-01	21.4
2018-01-01	23.5
2018-04-01	17.5