Quarter	Percent
1999-01-01	79.8
2000-01-01	76.8
2000-04-01	77.5
2000-07-01	78.1
2000-10-01	78.1
2001-01-01	75.4
2001-04-01	75.2
2001-07-01	75.9
2001-10-01	75
2002-01-01	72.5
2002-04-01	72.8
2002-07-01	73.5
2002-10-01	73.2
2003-01-01	71.9
2003-04-01	72.8
2003-07-01	73.7
2003-10-01	73.4
2004-01-01	72.2
2004-04-01	73.6
2004-07-01	74.5
2004-10-01	75.3
2005-01-01	74.6
2005-04-01	75.7
2005-07-01	76.8
2005-10-01	77.2
2006-01-01	75.8
2006-04-01	77.8
2006-07-01	79.3
2006-10-01	80.3
2007-01-01	79.7
2007-04-01	80.9
2007-07-01	81.5
2007-10-01	82.5
2008-01-01	82.7
2008-04-01	83.7
2008-07-01	84.9
2008-10-01	84.7
2009-01-01	83.3
2009-04-01	84
2009-07-01	84.4
2009-10-01	83.2
2010-01-01	81
2010-04-01	82.7
2010-07-01	83.4
2010-10-01	83
2011-01-01	82
2011-04-01	83.1
2011-07-01	83.6
2011-10-01	83.3
2012-01-01	82
2012-04-01	83.1
2012-07-01	83.6
2012-10-01	82.9
2013-01-01	81.4
2013-04-01	82.8
2013-07-01	83.5
2013-10-01	83
2014-01-01	82
2014-04-01	83.8
2014-07-01	85.2
2014-10-01	84.7
2015-01-01	83.9
2015-04-01	84.6
2015-07-01	85.6
2015-10-01	85.7
2016-01-01	85.0
2016-04-01	86.0
2016-07-01	86.7
2016-10-01	86.7
2017-01-01	86.5
2017-04-01	87.3
2017-07-01	88.0
2017-10-01	87.6
2018-01-01	87.3
2018-04-01	88.3