Quarter	Percent
2005-01-01	19.2
2005-04-01	15.9
2005-07-01	12.6
2005-10-01	16.2
2006-01-01	11.1
2006-07-01	11.6
2007-01-01	8.3
2007-07-01	7.3
2008-01-01	7.7
2008-04-01	11.9
2008-07-01	14.9
2008-10-01	17.2
2009-01-01	30.2
2009-04-01	36.7
2009-07-01	38.0
2009-10-01	35.8
2010-01-01	44.4
2010-04-01	41.3
2010-07-01	38.7
2010-10-01	32.2
2011-01-01	38.2
2011-04-01	38.1
2011-07-01	31.7
2011-10-01	31.2
2012-01-01	32.2
2012-04-01	31.0
2012-07-01	30.3
2012-10-01	25.8
2013-01-01	23.0
2013-04-01	21.4
2013-07-01	23.9
2013-10-01	23.6
2014-01-01	20.2
2014-04-01	22.7
2014-07-01	17.4
2014-10-01	18.4
2015-01-01	22.8
2015-04-01	16.3
2015-07-01	12.6
2015-10-01	11.9
2016-01-01	15.6
2016-04-01	16.3
2016-07-01	14.5
2016-10-01	17.2
2017-01-01	15.6
2017-04-01	14.5
2017-07-01	13.4
2017-10-01	14.7
2018-01-01	15.0
2018-04-01	11.4