Quarter	Percent
1999-04-01	76.5
2000-04-01	77
2001-04-01	77.5
2002-04-01	78
2003-04-01	78.8
2004-04-01	78.8
2005-01-01	79.3
2005-04-01	79.1
2005-07-01	78.9
2005-10-01	79.1
2006-01-01	80.3
2006-04-01	80.3
2006-07-01	80.3
2006-10-01	80.2
2007-01-01	80.6
2007-04-01	80.3
2007-07-01	80.7
2007-10-01	80.8
2008-01-01	80.3
2008-04-01	80.2
2008-07-01	80.6
2008-10-01	80.9
2009-01-01	80.4
2009-04-01	80.8
2009-07-01	81
2009-10-01	81.7
2010-01-01	80.9
2010-04-01	81.5
2010-07-01	81.2
2010-10-01	81.7
2011-01-01	81.6
2011-04-01	82.1
2011-07-01	82.3
2011-10-01	82.6
2012-01-01	82
2012-04-01	82.3
2012-07-01	82.1
2012-10-01	82.6
2013-01-01	82.4
2013-04-01	82.7
2013-07-01	82.5
2013-10-01	82.2
2014-01-01	82.3
2014-04-01	82.7
2014-07-01	82.5
2014-10-01	82.4
2015-01-01	82.5
2015-04-01	82.8
2015-07-01	82.2
2015-10-01	82.5
2016-01-01	82.5
2016-04-01	82.3
2016-07-01	82.7
2016-10-01	83.0
2017-01-01	82.4
2017-04-01	82.1
2017-07-01	82.6
2017-10-01	83.0
2018-01-01	82.7
2018-04-01	82.6