Quarter	Percent
2006-01-01	77.4
2006-04-01	74
2006-07-01	73.5
2006-10-01	74.9
2007-01-01	76.1
2007-04-01	73.5
2007-07-01	73.7
2007-10-01	76
2008-01-01	76.3
2008-04-01	72.9
2008-07-01	72.4
2008-10-01	73.8
2009-01-01	74.8
2009-04-01	71.5
2009-07-01	70.6
2009-10-01	71.8
2010-01-01	72.1
2010-04-01	69.5
2010-07-01	69.4
2010-10-01	70.5
2011-01-01	70.8
2011-04-01	67.9
2011-07-01	67.7
2011-10-01	69.4
2012-01-01	70.4
2012-04-01	67.4
2012-07-01	67.6
2012-10-01	67.5
2013-01-01	68.1
2013-04-01	65.5
2013-07-01	66.2
2013-10-01	67.2
2014-01-01	68.2
2014-04-01	65.7
2014-07-01	65.8
2014-10-01	66.1
2015-01-01	66.7
2015-04-01	64.4
2015-07-01	64.4
2015-10-01	64.9
2016-01-01	65.3
2016-04-01	63.4
2016-07-01	63.1
2016-10-01	63.5
2017-01-01	63.9
2017-04-01	62.1
2017-07-01	61.8
2017-10-01	62.1
2018-01-01	62.7
2018-04-01	61.5