Quarter	Percent
1999-04-01	89.3
2000-04-01	90.4
2001-04-01	90.8
2002-04-01	88
2003-01-01	84
2003-04-01	87.7
2003-07-01	88.3
2003-10-01	85.2
2004-01-01	82.9
2004-04-01	86.4
2004-07-01	88.1
2004-10-01	85.6
2005-01-01	82.9
2005-04-01	88.4
2005-07-01	90.3
2005-10-01	85.9
2006-01-01	85.5
2006-04-01	88.9
2006-07-01	89.5
2006-10-01	88.3
2007-01-01	88
2007-04-01	89.4
2007-07-01	90.4
2007-10-01	88.7
2008-01-01	87
2008-04-01	89.6
2008-07-01	88.6
2008-10-01	84
2009-01-01	78.1
2009-04-01	80.1
2009-07-01	82.8
2009-10-01	79
2010-01-01	78.5
2010-04-01	81.2
2010-07-01	81.3
2010-10-01	79.4
2011-01-01	77.1
2011-04-01	80.5
2011-07-01	82.4
2011-10-01	81.1
2012-01-01	78.8
2012-04-01	82.6
2012-07-01	83.6
2012-10-01	80.8
2013-01-01	79.7
2013-04-01	83.7
2013-07-01	86.1
2013-10-01	83.2
2014-01-01	82.1
2014-04-01	87.2
2014-07-01	87.3
2014-10-01	84.8
2015-01-01	85.1
2015-04-01	88.4
2015-07-01	89.7
2015-10-01	85.2
2016-01-01	87.0
2016-04-01	90.4
2016-07-01	91.4
2016-10-01	88.8
2017-01-01	88.0
2017-04-01	90.7
2017-07-01	89.0
2017-10-01	86.7
2018-01-01	86.1
2018-04-01	88.0