Quarter	Percent
2005-01-01	27.8
2005-04-01	27.0
2005-07-01	27.5
2005-10-01	28.2
2006-01-01	28.8
2006-04-01	29.3
2006-07-01	29.0
2006-10-01	30.1
2007-01-01	29.9
2007-04-01	28.5
2007-07-01	27.5
2007-10-01	29.0
2008-01-01	29.5
2008-04-01	28.2
2008-07-01	28.0
2008-10-01	28.0
2009-01-01	28.5
2009-04-01	27.8
2009-07-01	27.8
2009-10-01	29.0
2010-01-01	29.1
2010-04-01	28.6
2010-07-01	27.6
2010-10-01	26.9
2011-01-01	26.4
2011-04-01	26.1
2011-07-01	26.5
2011-10-01	26.8
2012-01-01	27.5
2012-04-01	26.3
2012-07-01	25.5
2012-10-01	26.0
2013-01-01	26.1
2013-04-01	25.5
2013-07-01	24.9
2013-10-01	24.7
2014-01-01	24.3
2014-04-01	24.3
2014-07-01	23.4
2014-10-01	24.1
2015-01-01	24.6
2015-04-01	24.2
2015-07-01	24.1
2015-10-01	23.7
2016-01-01	23.9
2016-04-01	22.3
2016-07-01	22.4
2016-10-01	22.8
2017-01-01	22.8
2017-04-01	22.6
2017-07-01	22.6
2017-10-01	22.4
2018-01-01	22.0
2018-04-01	21.1