Quarter	Percent
1999-01-01	68.6
2000-01-01	65.8
2000-04-01	65.1
2000-07-01	64.7
2000-10-01	65.1
2001-01-01	63.2
2001-04-01	63.3
2001-07-01	63.1
2001-10-01	64.8
2002-01-01	65.6
2002-04-01	66
2002-07-01	64.9
2002-10-01	67.3
2003-01-01	68.5
2003-04-01	68.1
2003-07-01	66.7
2003-10-01	67.7
2004-01-01	67.7
2004-04-01	68.8
2004-07-01	67.4
2004-10-01	68.2
2005-01-01	69.1
2005-04-01	68.9
2005-07-01	66.4
2005-10-01	68.3
2006-01-01	69.9
2006-04-01	69.9
2006-07-01	68.4
2006-10-01	69
2007-01-01	70.9
2007-04-01	71.7
2007-07-01	69.3
2007-10-01	70.7
2008-01-01	70.4
2008-04-01	71
2008-07-01	69.8
2008-10-01	70.5
2009-01-01	70.3
2009-04-01	71.2
2009-07-01	69.9
2009-10-01	71.1
2010-01-01	70.5
2010-04-01	70.6
2010-07-01	68.8
2010-10-01	71.6
2011-01-01	73.4
2011-04-01	72.1
2011-07-01	70.5
2011-10-01	71.6
2012-01-01	71.7
2012-04-01	71.5
2012-07-01	71.8
2012-10-01	71.6
2013-01-01	72.8
2013-04-01	72.3
2013-07-01	71.4
2013-10-01	71.9
2014-01-01	71.1
2014-04-01	70.7
2014-07-01	71.1
2014-10-01	72.5
2015-01-01	72.8
2015-04-01	73.3
2015-07-01	72.8
2015-10-01	73.3
2016-01-01	70.4
2016-04-01	71.1
2016-07-01	71.5
2016-10-01	71.3
2017-01-01	70.5
2017-04-01	70.9
2017-07-01	70.0
2017-10-01	70.0
2018-01-01	70.0
2018-04-01	68.6