Quarter	Percent
1998-01-01	32.2
1998-04-01	30
1998-07-01	29.7
1998-10-01	31.7
1999-01-01	30.7
1999-04-01	26.1
1999-07-01	28.3
1999-10-01	30.6
2000-01-01	29.7
2000-04-01	25.9
2000-07-01	27.2
2000-10-01	29.7
2001-01-01	29.2
2001-04-01	25.3
2001-07-01	27.1
2001-10-01	28.6
2002-01-01	28.2
2002-04-01	25.1
2002-07-01	26.6
2002-10-01	28.8
2003-01-01	28.1
2003-04-01	25.5
2003-07-01	27.9
2003-10-01	29.8
2004-01-01	29.5
2004-04-01	25.9
2004-07-01	27.3
2004-10-01	29.2
2005-01-01	28
2005-04-01	25.3
2005-07-01	27
2005-10-01	28.3
2006-01-01	27.7
2006-04-01	25
2006-07-01	26.4
2006-10-01	27.8
2007-01-01	27.1
2007-04-01	24.7
2007-07-01	25.8
2007-10-01	27.1
2008-01-01	27.1
2008-04-01	24.3
2008-07-01	25.7
2008-10-01	27.1
2009-01-01	27.1
2009-04-01	24.5
2009-07-01	26.5
2009-10-01	27.8
2010-01-01	28.4
2010-04-01	25.4
2010-07-01	27.5
2010-10-01	28.8
2011-01-01	28.7
2011-04-01	25.6
2011-07-01	26.6
2011-10-01	28.5
2012-01-01	27.8
2012-04-01	24.9
2012-07-01	25.4
2012-10-01	28.2
2013-01-01	27.2
2013-04-01	24.7
2013-07-01	26.8
2013-10-01	27.6
2014-01-01	27.3
2014-04-01	23.9
2014-07-01	25.6
2014-10-01	27.6
2015-01-01	26.8
2015-04-01	23.6
2015-07-01	24.9
2015-10-01	26.9
2016-01-01	26.6
2016-04-01	24.4
2016-07-01	25.3
2016-10-01	27.4
2017-01-01	26.3
2017-04-01	23.4
2017-07-01	25.1
2017-10-01	25.6
2018-01-01	24.3
2018-04-01	21.8