Quarter	Percent
1998-04-01	81.2
1999-01-01	82.6
1999-04-01	82.5
1999-07-01	82.1
1999-10-01	81.9
2000-01-01	82.4
2000-04-01	82.8
2000-07-01	82.7
2000-10-01	81.7
2001-01-01	81.6
2001-04-01	80.9
2001-07-01	80.6
2001-10-01	81.7
2002-01-01	81.8
2002-04-01	81.7
2002-07-01	82
2002-10-01	82.2
2003-01-01	82
2003-04-01	81.8
2003-07-01	82.2
2003-10-01	83.2
2004-01-01	83.2
2004-04-01	82.8
2004-07-01	83.5
2004-10-01	84
2005-01-01	84.6
2005-04-01	84.4
2005-07-01	84.8
2005-10-01	84.4
2006-01-01	83.7
2006-04-01	84.5
2006-07-01	84.5
2006-10-01	85.2
2007-01-01	85.3
2007-04-01	85.1
2007-07-01	85.1
2007-10-01	85.7
2008-01-01	86.1
2008-04-01	85.5
2008-07-01	85.9
2008-10-01	85.3
2009-01-01	86.5
2009-04-01	85.1
2009-07-01	85.1
2009-10-01	85.6
2010-01-01	86.8
2010-04-01	85.7
2010-07-01	85.9
2010-10-01	86.9
2011-01-01	84.1
2011-04-01	85.2
2011-07-01	84.8
2011-10-01	84.9
2012-01-01	84.5
2012-04-01	84.6
2012-07-01	85.3
2012-10-01	85.6
2013-01-01	85.1
2013-04-01	85.5
2013-07-01	85.6
2013-10-01	85.2
2014-01-01	85.9
2014-04-01	85.4
2014-07-01	85.7
2014-10-01	85.5
2015-01-01	85.8
2015-04-01	84.6
2015-07-01	84.8
2015-10-01	85.1
2016-01-01	84.9
2016-04-01	84.7
2016-07-01	84.9
2016-10-01	86.0
2017-01-01	84.9
2017-04-01	85.0
2017-07-01	84.4
2017-10-01	85.2
2018-01-01	85.0
2018-04-01	84.6