Quarter	Percent
1998-01-01	29.1
1998-04-01	26.9
1998-07-01	26.1
1998-10-01	28.5
1999-01-01	28
1999-04-01	23.6
1999-07-01	25.3
1999-10-01	27.7
2000-01-01	27.2
2000-04-01	23.2
2000-07-01	24.4
2000-10-01	27.1
2001-01-01	26.7
2001-04-01	22.9
2001-07-01	24.2
2001-10-01	26.1
2002-01-01	26.4
2002-04-01	22.8
2002-07-01	24.3
2002-10-01	26.7
2003-01-01	26.6
2003-04-01	23.2
2003-07-01	24.9
2003-10-01	27.5
2004-01-01	27.3
2004-04-01	23.8
2004-07-01	24.9
2004-10-01	27.1
2005-01-01	26.5
2005-04-01	23.4
2005-07-01	24.9
2005-10-01	26.3
2006-01-01	26
2006-04-01	23.2
2006-07-01	24
2006-10-01	26
2007-01-01	26
2007-04-01	22.7
2007-07-01	23.6
2007-10-01	25.5
2008-01-01	25.4
2008-04-01	21.9
2008-07-01	23.6
2008-10-01	25.2
2009-01-01	25.8
2009-04-01	22.7
2009-07-01	25
2009-10-01	26.6
2010-01-01	26.6
2010-04-01	23.4
2010-07-01	25.2
2010-10-01	26.8
2011-01-01	26.4
2011-04-01	23
2011-07-01	24.5
2011-10-01	26.2
2012-01-01	26.1
2012-04-01	22.8
2012-07-01	23.9
2012-10-01	26.3
2013-01-01	26
2013-04-01	22.5
2013-07-01	24.6
2013-10-01	26.3
2014-01-01	25.9
2014-04-01	22.4
2014-07-01	24.4
2014-10-01	25.8
2015-01-01	25.4
2015-04-01	22.2
2015-07-01	23.5
2015-10-01	25.6
2016-01-01	25.1
2016-04-01	22.2
2016-07-01	23.6
2016-10-01	25.5
2017-01-01	24.8
2017-04-01	21.5
2017-07-01	23.0
2017-10-01	23.7
2018-01-01	23.1
2018-04-01	20.3