Quarter	Percent
1999-04-01	91.8
2000-04-01	95.5
2001-04-01	93.3
2002-04-01	90.2
2003-01-01	87
2003-04-01	84.8
2003-07-01	85.3
2003-10-01	91
2004-01-01	85.9
2004-04-01	83.9
2004-07-01	86.1
2004-10-01	91.4
2005-01-01	88.7
2005-04-01	87
2005-07-01	89.1
2005-10-01	90.6
2006-01-01	91.4
2006-04-01	88.4
2006-07-01	85.6
2006-10-01	89.4
2007-01-01	91.2
2007-04-01	90.5
2007-07-01	86.9
2007-10-01	88.5
2008-01-01	87.8
2008-04-01	89.2
2008-07-01	87.5
2008-10-01	89.1
2009-01-01	84.8
2009-04-01	82.6
2009-07-01	83.6
2009-10-01	85.9
2010-01-01	84.6
2010-04-01	82.5
2010-07-01	80.9
2010-10-01	84.9
2011-01-01	80.4
2011-04-01	81.5
2011-07-01	80.7
2011-10-01	85.5
2012-01-01	82.3
2012-04-01	82.7
2012-07-01	83.3
2012-10-01	84.3
2013-01-01	85.7
2013-04-01	86.5
2013-07-01	87.6
2013-10-01	88.8
2014-01-01	87.9
2014-04-01	89.8
2014-07-01	88.4
2014-10-01	88.8
2015-01-01	88.1
2015-04-01	88.0
2015-07-01	90.6
2015-10-01	89.0
2016-01-01	87.7
2016-04-01	91.5
2016-07-01	91.9
2016-10-01	87.6
2017-01-01	90.6
2017-04-01	89.1
2017-07-01	86.8
2017-10-01	89.8
2018-01-01	84.1
2018-04-01	84.6