Quarter	Percent
2005-01-01	34.0
2005-04-01	33.5
2005-07-01	33.8
2005-10-01	34.4
2006-01-01	34.8
2006-04-01	35.5
2006-07-01	35.3
2006-10-01	36.1
2007-01-01	35.8
2007-04-01	34.5
2007-07-01	33.5
2007-10-01	34.8
2008-01-01	35.2
2008-04-01	33.9
2008-07-01	33.8
2008-10-01	34.1
2009-01-01	34.8
2009-04-01	34.0
2009-07-01	33.7
2009-10-01	34.7
2010-01-01	35.2
2010-04-01	34.6
2010-07-01	33.7
2010-10-01	33.1
2011-01-01	32.8
2011-04-01	32.1
2011-07-01	32.8
2011-10-01	33.2
2012-01-01	33.6
2012-04-01	32.2
2012-07-01	31.5
2012-10-01	32.4
2013-01-01	32.3
2013-04-01	31.5
2013-07-01	31.1
2013-10-01	31.0
2014-01-01	30.5
2014-04-01	30.4
2014-07-01	29.7
2014-10-01	30.5
2015-01-01	30.8
2015-04-01	30.2
2015-07-01	30.3
2015-10-01	30.0
2016-01-01	30.2
2016-04-01	28.4
2016-07-01	28.5
2016-10-01	29.0
2017-01-01	28.8
2017-04-01	28.6
2017-07-01	28.7
2017-10-01	28.7
2018-01-01	28.2
2018-04-01	27.2