Quarter	Percent
2006-01-01	22.6
2006-04-01	26
2006-07-01	26.5
2006-10-01	25.1
2007-01-01	23.9
2007-04-01	26.5
2007-07-01	26.3
2007-10-01	24
2008-01-01	23.7
2008-04-01	27.1
2008-07-01	27.6
2008-10-01	26.2
2009-01-01	25.2
2009-04-01	28.5
2009-07-01	29.4
2009-10-01	28.2
2010-01-01	27.9
2010-04-01	30.5
2010-07-01	30.6
2010-10-01	29.5
2011-01-01	29.2
2011-04-01	32.1
2011-07-01	32.3
2011-10-01	30.6
2012-01-01	29.6
2012-04-01	32.6
2012-07-01	32.4
2012-10-01	32.5
2013-01-01	31.9
2013-04-01	34.5
2013-07-01	33.8
2013-10-01	32.8
2014-01-01	31.8
2014-04-01	34.3
2014-07-01	34.2
2014-10-01	33.9
2015-01-01	33.3
2015-04-01	35.6
2015-07-01	35.6
2015-10-01	35.1
2016-01-01	34.7
2016-04-01	36.6
2016-07-01	36.9
2016-10-01	36.5
2017-01-01	36.1
2017-04-01	37.9
2017-07-01	38.2
2017-10-01	37.9
2018-01-01	37.3
2018-04-01	38.5