Quarter	Percent
1999-04-01	30
2000-01-01	29
2000-04-01	29.5
2000-07-01	28.8
2000-10-01	29.2
2001-01-01	30
2001-04-01	30.2
2001-07-01	28.9
2001-10-01	29.4
2002-01-01	31.2
2002-04-01	31.6
2002-07-01	30.4
2002-10-01	29.6
2003-01-01	30.8
2003-04-01	29.4
2003-07-01	28.7
2003-10-01	29.3
2004-01-01	29.6
2004-04-01	29.3
2004-07-01	29.1
2004-10-01	30.1
2005-01-01	29.6
2005-04-01	28.8
2005-07-01	29.8
2005-10-01	29.1
2006-01-01	27.5
2006-04-01	26.2
2006-07-01	27.7
2006-10-01	27.3
2007-01-01	27.2
2007-04-01	26.2
2007-07-01	26.3
2007-10-01	27.4
2008-01-01	27.2
2008-04-01	27
2008-07-01	24.7
2008-10-01	24.3
2009-01-01	26
2009-04-01	26.1
2009-07-01	25.3
2009-10-01	26.5
2010-01-01	25.9
2010-04-01	26.3
2010-07-01	26.2
2010-10-01	26
2011-01-01	25.8
2011-04-01	25.5
2011-07-01	24.3
2011-10-01	25.4
2012-01-01	25.3
2012-04-01	25.2
2012-07-01	24.5
2012-10-01	25.8
2013-01-01	24.9
2013-04-01	24.4
2013-07-01	25.2
2013-10-01	25.1
2014-01-01	26
2014-04-01	24.6
2014-07-01	23.8
2014-10-01	24.6
2015-01-01	25.1
2015-04-01	23.2
2015-07-01	21.8
2015-10-01	23.2
2016-01-01	24.6
2016-04-01	21.5
2016-07-01	20.7
2016-10-01	23.3
2017-01-01	22.3
2017-04-01	21.1
2017-07-01	20.9
2017-10-01	20.4
2018-01-01	21.0
2018-04-01	21.2