Quarter	Percent
1999-01-01	86.4
2000-01-01	86.4
2001-01-01	86.1
2002-01-01	86.1
2003-01-01	87.1
2003-04-01	86.8
2003-07-01	86.3
2003-10-01	87.0
2004-01-01	87.2
2004-04-01	87.2
2004-07-01	86.6
2004-10-01	87.4
2005-01-01	87.4
2005-04-01	87.2
2005-07-01	87.0
2005-10-01	87.5
2006-01-01	87.6
2006-04-01	87.4
2006-07-01	87.5
2006-10-01	87.8
2007-01-01	87.9
2007-04-01	87.9
2007-07-01	87.8
2007-10-01	88.2
2008-01-01	88.4
2008-04-01	88.6
2008-07-01	88.2
2008-10-01	88.8
2009-01-01	88.6
2009-04-01	88.8
2009-07-01	88.2
2009-10-01	88.8
2010-01-01	89.0
2010-04-01	88.7
2010-07-01	88.3
2010-10-01	88.7
2011-01-01	88.6
2011-04-01	88.2
2011-07-01	87.8
2011-10-01	88.4
2012-01-01	88.3
2012-04-01	88.3
2012-07-01	87.7
2012-10-01	88.4
2013-01-01	88.2
2013-04-01	88.4
2013-07-01	88.1
2013-10-01	88.5
2014-01-01	88.1
2014-04-01	87.8
2014-07-01	87.4
2014-10-01	88.1
2015-01-01	87.5
2015-04-01	87.4
2015-07-01	87.3
2015-10-01	87.7
2016-01-01	87.8
2016-04-01	87.4
2016-07-01	87.2
2016-10-01	87.6
2017-01-01	87.1
2017-04-01	87.6
2017-07-01	87.4
2017-10-01	87.6
2018-01-01	87.7
2018-04-01	87.8