Quarter	Percent
2005-01-01	48.7
2005-04-01	45.6
2005-07-01	46.1
2005-10-01	46.6
2006-01-01	46.0
2006-04-01	46.5
2006-07-01	47.7
2006-10-01	48.2
2007-01-01	44.8
2007-04-01	44.2
2007-07-01	43.0
2007-10-01	46.9
2008-01-01	46.2
2008-04-01	44.3
2008-07-01	44.0
2008-10-01	43.8
2009-01-01	42.6
2009-04-01	41.8
2009-07-01	42.5
2009-10-01	44.4
2010-01-01	43.8
2010-04-01	42.8
2010-07-01	44.1
2010-10-01	43.4
2011-01-01	42.4
2011-04-01	42.0
2011-07-01	41.9
2011-10-01	41.9
2012-01-01	41.8
2012-04-01	41.8
2012-07-01	40.1
2012-10-01	41.5
2013-01-01	40.7
2013-04-01	40.7
2013-07-01	40.2
2013-10-01	38.0
2014-01-01	37.1
2014-04-01	38.2
2014-07-01	36.3
2014-10-01	36.4
2015-01-01	35.6
2015-04-01	33.5
2015-07-01	33.7
2015-10-01	32.5
2016-01-01	30.9
2016-04-01	29.7
2016-07-01	29.8
2016-10-01	29.5
2017-01-01	29.4
2017-04-01	28.7
2017-07-01	29.4
2017-10-01	27.4
2018-01-01	26.4
2018-04-01	26.6