Quarter	Percent
1999-01-01	67.8
1999-04-01	68.2
1999-07-01	68.5
1999-10-01	67.7
2000-01-01	68
2000-04-01	68.6
2000-07-01	68.4
2000-10-01	68.5
2001-01-01	68.1
2001-04-01	68.3
2001-07-01	69.4
2001-10-01	69.4
2002-01-01	68.1
2002-04-01	69.1
2002-07-01	68.8
2002-10-01	68.4
2003-01-01	67.5
2003-04-01	68.1
2003-07-01	68.7
2003-10-01	67.9
2004-01-01	67.6
2004-04-01	68.7
2004-07-01	69.4
2004-10-01	68.4
2005-01-01	67.9
2005-04-01	68.3
2005-07-01	68.8
2005-10-01	69.3
2006-01-01	68.8
2006-04-01	69.3
2006-07-01	70.4
2006-10-01	69.9
2007-01-01	69.3
2007-04-01	69.5
2007-07-01	69.2
2007-10-01	69
2008-01-01	68.9
2008-04-01	70.1
2008-07-01	70.4
2008-10-01	69.7
2009-01-01	68
2009-04-01	67.6
2009-07-01	67.6
2009-10-01	65.6
2010-01-01	65
2010-04-01	65.5
2010-07-01	65.5
2010-10-01	64.8
2011-01-01	64.3
2011-04-01	65
2011-07-01	65.3
2011-10-01	64.3
2012-01-01	63.8
2012-04-01	64.3
2012-07-01	64.2
2012-10-01	63.9
2013-01-01	63.2
2013-04-01	63.9
2013-07-01	64.1
2013-10-01	63.3
2014-01-01	62.5
2014-04-01	63.6
2014-07-01	64.6
2014-10-01	64.5
2015-01-01	63.9
2015-04-01	64.1
2015-07-01	64.3
2015-10-01	64.6
2016-01-01	65.4
2016-04-01	66.2
2016-07-01	66.0
2016-10-01	65.4
2017-01-01	64.1
2017-04-01	64.8
2017-07-01	65.4
2017-10-01	65.1
2018-01-01	65.1
2018-04-01	66.1