Quarter	Percent
1999-01-01	65.6
1999-04-01	65.8
1999-07-01	66.5
1999-10-01	66.4
2000-01-01	66.3
2000-04-01	66.7
2000-07-01	67.1
2000-10-01	67.3
2001-01-01	67.1
2001-04-01	67.1
2001-07-01	67.1
2001-10-01	66.6
2002-01-01	66.4
2002-04-01	66.7
2002-07-01	66.6
2002-10-01	66.2
2003-01-01	66.4
2003-04-01	67.7
2003-07-01	67.9
2003-10-01	67.8
2004-01-01	66.9
2004-04-01	67
2004-07-01	66.9
2004-10-01	67
2005-01-01	66.7
2005-04-01	67.2
2005-07-01	67.6
2005-10-01	67.4
2006-01-01	67.5
2006-04-01	67.8
2006-07-01	67.7
2006-10-01	68.1
2007-01-01	67.7
2007-04-01	67.8
2007-07-01	68
2007-10-01	68
2008-01-01	67.3
2008-04-01	67.9
2008-07-01	68.4
2008-10-01	68.2
2009-01-01	67
2009-04-01	67
2009-07-01	66.9
2009-10-01	66.7
2010-01-01	66.8
2010-04-01	67.3
2010-07-01	67.4
2010-10-01	66.6
2011-01-01	65.6
2011-04-01	66.6
2011-07-01	66.8
2011-10-01	67.5
2012-01-01	67.3
2012-04-01	69
2012-07-01	70.2
2012-10-01	69.7
2013-01-01	69
2013-04-01	69.8
2013-07-01	70.3
2013-10-01	71.1
2014-01-01	72.5
2014-04-01	72.7
2014-07-01	73.8
2014-10-01	73.7
2015-01-01	73.7
2015-04-01	74.3
2015-07-01	74.9
2015-10-01	74.8
2016-01-01	75.0
2016-04-01	76.3
2016-07-01	76.5
2016-10-01	77.0
2017-01-01	76.4
2017-04-01	77.1
2017-07-01	77.8
2017-10-01	77.4
2018-01-01	77.2
2018-04-01	78.3