Quarter	Percent
2005-01-01	37.2
2005-04-01	36.7
2005-07-01	37.0
2005-10-01	37.5
2006-01-01	38.2
2006-04-01	38.8
2006-07-01	38.5
2006-10-01	39.3
2007-01-01	39.1
2007-04-01	37.9
2007-07-01	37.0
2007-10-01	38.1
2008-01-01	38.7
2008-04-01	37.5
2008-07-01	37.4
2008-10-01	37.7
2009-01-01	38.4
2009-04-01	37.7
2009-07-01	37.5
2009-10-01	38.4
2010-01-01	39.0
2010-04-01	38.4
2010-07-01	37.6
2010-10-01	37.0
2011-01-01	36.9
2011-04-01	36.3
2011-07-01	37.1
2011-10-01	37.5
2012-01-01	37.8
2012-04-01	36.5
2012-07-01	35.9
2012-10-01	36.8
2013-01-01	36.7
2013-04-01	35.9
2013-07-01	35.5
2013-10-01	35.4
2014-01-01	35.0
2014-04-01	35.1
2014-07-01	34.5
2014-10-01	35.2
2015-01-01	35.4
2015-04-01	34.9
2015-07-01	35.2
2015-10-01	35.0
2016-01-01	35.0
2016-04-01	33.4
2016-07-01	33.6
2016-10-01	34.0
2017-01-01	33.7
2017-04-01	33.6
2017-07-01	33.6
2017-10-01	33.5
2018-01-01	33.0
2018-04-01	32.3