Quarter	Percent
1998-01-01	89.1
1998-04-01	90
1998-07-01	90
1998-10-01	90.1
1999-01-01	90
1999-04-01	89.5
1999-07-01	89.6
1999-10-01	89.3
2000-01-01	89.5
2000-04-01	89.9
2000-07-01	90.0
2000-10-01	90.5
2001-01-01	90.3
2001-04-01	90.1
2001-07-01	90.1
2001-10-01	90.1
2002-01-01	89.9
2002-04-01	89.6
2002-07-01	89.5
2002-10-01	88.2
2003-01-01	87.4
2003-04-01	87.9
2003-07-01	88
2003-10-01	88.1
2004-01-01	88
2004-04-01	87.9
2004-07-01	87.5
2004-10-01	87
2005-01-01	86.8
2005-04-01	86.7
2005-07-01	86.9
2005-10-01	86.9
2006-01-01	87.5
2006-04-01	87.6
2006-07-01	87.7
2006-10-01	87.2
2007-01-01	86.9
2007-04-01	87.2
2007-07-01	87.3
2007-10-01	87.6
2008-01-01	87.7
2008-04-01	87.9
2008-07-01	87.5
2008-10-01	87.4
2009-01-01	85.8
2009-04-01	85.5
2009-07-01	83.6
2009-10-01	83.8
2010-01-01	84.3
2010-04-01	84
2010-07-01	84.3
2010-10-01	83.7
2011-01-01	82
2011-04-01	82.6
2011-07-01	82.2
2011-10-01	80.2
2012-01-01	79.4
2012-04-01	79.4
2012-07-01	78.4
2012-10-01	77.3
2013-01-01	75.6
2013-04-01	76.7
2013-07-01	77.7
2013-10-01	78.3
2014-01-01	78.6
2014-04-01	81
2014-07-01	81.5
2014-10-01	81.4
2015-01-01	80.7
2015-04-01	81.6
2015-07-01	82.4
2015-10-01	82.6
2016-01-01	81.9
2016-04-01	82.9
2016-07-01	83.6
2016-10-01	83.6
2017-01-01	83.9
2017-04-01	85.7
2017-07-01	86.4
2017-10-01	86.4
2018-01-01	86.8
2018-04-01	87.4