Quarter	Percent
2005-01-01	29.1
2005-04-01	30.1
2005-07-01	29.9
2005-10-01	29.4
2006-01-01	29.2
2006-04-01	28.8
2006-07-01	30.9
2006-10-01	27.7
2007-01-01	28.5
2007-04-01	32.7
2007-07-01	33.2
2007-10-01	32.1
2008-01-01	33.0
2008-04-01	35.6
2008-07-01	36.5
2008-10-01	33.3
2009-01-01	34.5
2009-04-01	34.6
2009-07-01	31.4
2009-10-01	30.1
2010-01-01	30.9
2010-04-01	29.4
2010-07-01	31.4
2010-10-01	33.6
2011-01-01	32.7
2011-04-01	32.0
2011-07-01	32.3
2011-10-01	31.2
2012-01-01	29.0
2012-04-01	31.8
2012-07-01	34.0
2012-10-01	34.7
2013-01-01	34.6
2013-04-01	34.3
2013-07-01	37.8
2013-10-01	36.4
2014-01-01	36.5
2014-04-01	38.5
2014-07-01	41.2
2014-10-01	38.2
2015-01-01	37.2
2015-04-01	36.8
2015-07-01	36.1
2015-10-01	36.8
2016-01-01	35.8
2016-04-01	39.6
2016-07-01	40.0
2016-10-01	39.5
2017-01-01	38.8
2017-04-01	38.4
2017-07-01	37.6
2017-10-01	36.2
2018-01-01	37.3
2018-04-01	37.0