Quarter	Percent
1998-01-01	89.8
1998-04-01	90.5
1998-07-01	90.4
1998-10-01	90.4
1999-01-01	90.2
1999-04-01	90.5
1999-07-01	90.6
1999-10-01	90.6
2000-01-01	90.3
2000-04-01	90.4
2000-07-01	90.7
2000-10-01	90.9
2001-01-01	91
2001-04-01	90.6
2001-07-01	90.7
2001-10-01	90.7
2002-01-01	90.9
2002-04-01	90.9
2002-07-01	90.9
2002-10-01	91.4
2003-01-01	91.4
2003-04-01	91.4
2003-07-01	91.3
2003-10-01	91.7
2004-01-01	91.2
2004-04-01	91.7
2004-07-01	91.5
2004-10-01	91.7
2005-01-01	91.2
2005-04-01	91.5
2005-07-01	90.9
2005-10-01	91.5
2006-01-01	91.4
2006-04-01	91.9
2006-07-01	90.8
2006-10-01	91.3
2007-01-01	90.6
2007-04-01	91.1
2007-07-01	90.9
2007-10-01	91.4
2008-01-01	90.9
2008-04-01	91.5
2008-07-01	90.7
2008-10-01	91
2009-01-01	90.2
2009-04-01	90.3
2009-07-01	89.8
2009-10-01	89.7
2010-01-01	89.6
2010-04-01	89.9
2010-07-01	88.9
2010-10-01	89.3
2011-01-01	89.1
2011-04-01	89.6
2011-07-01	89.1
2011-10-01	89.1
2012-01-01	89.4
2012-04-01	89.7
2012-07-01	88.8
2012-10-01	89.6
2013-01-01	88.9
2013-04-01	88.6
2013-07-01	87.7
2013-10-01	88.1
2014-01-01	88
2014-04-01	87.5
2014-07-01	87.2
2014-10-01	88.1
2015-01-01	87.4
2015-04-01	87.9
2015-07-01	87.5
2015-10-01	88.1
2016-01-01	87.6
2016-04-01	88.7
2016-07-01	88.2
2016-10-01	88.4
2017-01-01	88.6
2017-04-01	88.6
2017-07-01	88.4
2017-10-01	88.4
2018-01-01	87.9
2018-04-01	89.1