Quarter	Percent
1998-01-01	75.1
1998-04-01	75.3
1998-07-01	74.6
1998-10-01	75.3
1999-01-01	75.3
1999-04-01	75.8
1999-07-01	75.7
1999-10-01	76.1
2000-01-01	77
2000-04-01	77.1
2000-07-01	77.9
2000-10-01	77.6
2001-01-01	78.7
2001-04-01	78.1
2001-07-01	77.8
2001-10-01	78.0
2002-01-01	77.6
2002-04-01	78.3
2002-07-01	78.8
2002-10-01	78.6
2003-01-01	79.3
2003-04-01	79.9
2003-07-01	79.5
2003-10-01	79.8
2004-01-01	80
2004-04-01	80.5
2004-07-01	80.5
2004-10-01	81.2
2005-01-01	81.3
2005-04-01	81.5
2005-07-01	81.7
2005-10-01	82.2
2006-01-01	82.4
2006-04-01	82.7
2006-07-01	82.7
2006-10-01	82.7
2007-01-01	82.7
2007-04-01	82.7
2007-07-01	82.8
2007-10-01	82.8
2008-01-01	82.7
2008-04-01	83.3
2008-07-01	82.8
2008-10-01	82.7
2009-01-01	83.1
2009-04-01	83.2
2009-07-01	83.1
2009-10-01	83.7
2010-01-01	84.6
2010-04-01	85
2010-07-01	85.1
2010-10-01	84.7
2011-01-01	84.6
2011-04-01	85.4
2011-07-01	83.8
2011-10-01	84.2
2012-01-01	85.1
2012-04-01	85.3
2012-07-01	84.8
2012-10-01	85
2013-01-01	85.2
2013-04-01	85.3
2013-07-01	85.3
2013-10-01	86.3
2014-01-01	85.8
2014-04-01	86.2
2014-07-01	85.6
2014-10-01	85.8
2015-01-01	86.0
2015-04-01	86.4
2015-07-01	85.6
2015-10-01	86.2
2016-01-01	86.5
2016-04-01	86.1
2016-07-01	86.9
2016-10-01	86.8
2017-01-01	86.9
2017-04-01	86.9
2017-07-01	87.1
2017-10-01	87.2
2018-01-01	87.2
2018-04-01	87.6