Quarter	Percent
1998-04-01	70.8
1999-04-01	68.5
2000-04-01	70.6
2001-04-01	68.6
2002-04-01	70.4
2003-04-01	70.4
2004-04-01	68.1
2005-04-01	66.6
2006-04-01	70.2
2007-04-01	70.2
2008-04-01	68.1
2009-04-01	66.1
2010-01-01	67.6
2010-04-01	68.2
2010-07-01	71.1
2010-10-01	68.4
2011-01-01	68.3
2011-04-01	66.9
2011-07-01	70.7
2011-10-01	70.8
2012-01-01	67.0
2012-04-01	66.0
2012-07-01	71.7
2012-10-01	70.9
2013-01-01	70.1
2013-04-01	67.4
2013-07-01	68.9
2013-10-01	69.2
2014-01-01	67.7
2014-04-01	67.1
2014-07-01	70.4
2014-10-01	68.2
2015-01-01	65.1
2015-04-01	65.4
2015-07-01	68.5
2015-10-01	68.1
2016-01-01	68.0
2016-04-01	64.3
2016-07-01	68.2
2016-10-01	70.6
2017-01-01	68.2
2017-04-01	67.6
2017-07-01	72.7
2017-10-01	69.6
2018-01-01	66.8
2018-04-01	66.9