Quarter	Percent
1998-01-01	25.3
1998-04-01	34.6
1998-07-01	16.9
1998-10-01	18.4
1999-01-01	23.3
1999-04-01	28.6
1999-07-01	14.9
1999-10-01	17.8
2000-01-01	24.8
2000-04-01	28.4
2000-07-01	14.1
2000-10-01	17.2
2001-01-01	21.2
2001-04-01	26.6
2001-07-01	13.7
2001-10-01	16.2
2002-01-01	23.5
2002-04-01	28.2
2002-07-01	13.8
2002-10-01	17.2
2003-01-01	23.6
2003-04-01	27.8
2003-07-01	15.8
2003-10-01	18.5
2004-01-01	22.9
2004-04-01	27.5
2004-07-01	14.4
2004-10-01	16.8
2005-01-01	22.1
2005-04-01	27
2005-07-01	13.9
2005-10-01	16.1
2006-01-01	20.9
2006-04-01	26
2006-07-01	12.4
2006-10-01	14.4
2007-01-01	20.4
2007-04-01	21.7
2007-07-01	10.3
2007-10-01	13.4
2008-01-01	17.1
2008-04-01	22.2
2008-07-01	11.2
2008-10-01	14.2
2009-01-01	19.1
2009-04-01	28.3
2009-07-01	16.3
2009-10-01	20.3
2010-01-01	24.7
2010-04-01	27.6
2010-07-01	14.2
2010-10-01	18
2011-01-01	22.8
2011-04-01	25.7
2011-07-01	14.3
2011-10-01	16.2
2012-01-01	21.7
2012-04-01	23.7
2012-07-01	13.7
2012-10-01	16
2013-01-01	22.4
2013-04-01	26.2
2013-07-01	13.4
2013-10-01	16.2
2014-01-01	23.5
2014-04-01	25.6
2014-07-01	13.5
2014-10-01	18.8
2015-01-01	24.6
2015-04-01	29.0
2015-07-01	16.3
2015-10-01	18.2
2016-01-01	23.1
2016-04-01	26.3
2016-07-01	14.2
2016-10-01	15.9
2017-01-01	23.4
2017-04-01	27.4
2017-07-01	14.1
2017-10-01	14.3
2018-01-01	21.1
2018-04-01	21.6