Quarter	Percent
2005-01-01	31.2
2005-04-01	30.7
2005-07-01	30.8
2005-10-01	30.5
2006-01-01	30.6
2006-04-01	30.2
2006-07-01	30.2
2006-10-01	30.0
2007-01-01	30.4
2007-04-01	29.9
2007-07-01	30.1
2007-10-01	29.6
2008-01-01	29.9
2008-04-01	29.4
2008-07-01	29.6
2008-10-01	29.2
2009-01-01	29.5
2009-04-01	29.1
2009-07-01	29.0
2009-10-01	28.9
2010-01-01	29.1
2010-04-01	28.7
2010-07-01	29.0
2010-10-01	28.8
2011-01-01	29.0
2011-04-01	28.6
2011-07-01	28.8
2011-10-01	28.5
2012-01-01	28.7
2012-04-01	28.2
2012-07-01	28.4
2012-10-01	28.1
2013-01-01	28.4
2013-04-01	28.0
2013-07-01	28.2
2013-10-01	28.0
2014-01-01	28.1
2014-04-01	28.0
2014-07-01	28.2
2014-10-01	27.8
2015-01-01	28.1
2015-04-01	27.8
2015-07-01	28.1
2015-10-01	27.5
2016-01-01	27.7
2016-04-01	27.4
2016-07-01	27.4
2016-10-01	27.1
2017-01-01	27.3
2017-04-01	27.0