Quarter	Percent
1999-01-01	76.6
1999-04-01	77
1999-07-01	77.4
1999-10-01	77.3
2000-01-01	76.8
2000-04-01	77.3
2000-07-01	77.6
2000-10-01	77.6
2001-01-01	77.1
2001-04-01	77.1
2001-07-01	77.3
2001-10-01	76.8
2002-01-01	76.7
2002-04-01	77
2002-07-01	77.3
2002-10-01	77
2003-01-01	76.9
2003-04-01	77.9
2003-07-01	78.3
2003-10-01	78.2
2004-01-01	77.6
2004-04-01	77.8
2004-07-01	78
2004-10-01	78
2005-01-01	77.9
2005-04-01	78.6
2005-07-01	79.3
2005-10-01	79.1
2006-01-01	79.3
2006-04-01	80
2006-07-01	80.1
2006-10-01	80.3
2007-01-01	79.7
2007-04-01	80.1
2007-07-01	80.4
2007-10-01	80.4
2008-01-01	79.8
2008-04-01	80.2
2008-07-01	80.8
2008-10-01	80.4
2009-01-01	80
2009-04-01	80.3
2009-07-01	80.4
2009-10-01	80.4
2010-01-01	80.6
2010-04-01	81
2010-07-01	81.2
2010-10-01	80.7
2011-01-01	80.3
2011-04-01	81.3
2011-07-01	81.6
2011-10-01	81.8
2012-01-01	82.1
2012-04-01	82.8
2012-07-01	83.4
2012-10-01	83.2
2013-01-01	82.4
2013-04-01	83.4
2013-07-01	83.7
2013-10-01	83.7
2014-01-01	84.5
2014-04-01	84.9
2014-07-01	85.4
2014-10-01	85.2
2015-01-01	85.4
2015-04-01	85.8
2015-07-01	86.1
2015-10-01	85.9
2016-01-01	85.6
2016-04-01	86.2
2016-07-01	86.4
2016-10-01	86.3
2017-01-01	86.2
2017-04-01	86.9
2017-07-01	87.2
2017-10-01	87.0
2018-01-01	87.0
2018-04-01	87.4