Quarter	Percent
1998-04-01	71.2
1999-04-01	72.9
2000-04-01	72.1
2001-01-01	72.5
2001-04-01	72.5
2001-07-01	73.4
2001-10-01	73.8
2002-01-01	73.9
2002-04-01	74.3
2002-07-01	74.4
2002-10-01	74.3
2003-01-01	74.1
2003-04-01	74.9
2003-07-01	75.3
2003-10-01	75.4
2004-01-01	75.6
2004-04-01	75.5
2004-07-01	76
2004-10-01	75.3
2005-01-01	76.4
2005-04-01	75.8
2005-07-01	76.8
2005-10-01	76.5
2006-01-01	76.4
2006-04-01	75.9
2006-07-01	75.9
2006-10-01	75.9
2007-01-01	76
2007-04-01	76.2
2007-07-01	76.3
2007-10-01	76.4
2008-01-01	76.3
2008-04-01	76.3
2008-07-01	76.5
2008-10-01	76.9
2009-01-01	77.3
2009-04-01	76.9
2009-07-01	78
2009-10-01	78.9
2010-01-01	78.7
2010-04-01	79.1
2010-07-01	79.6
2010-10-01	79.8
2011-01-01	79
2011-04-01	80.3
2011-07-01	79.9
2011-10-01	80.2
2012-01-01	80.3
2012-04-01	80.9
2012-07-01	80.8
2012-10-01	81.6
2013-01-01	81.3
2013-04-01	81.5
2013-07-01	82
2013-10-01	81.9
2014-01-01	81.3
2014-04-01	81.6
2014-07-01	81.3
2014-10-01	81.9
2015-01-01	81.8
2015-04-01	81.8
2015-07-01	81.2
2015-10-01	82.3
2016-01-01	82.2
2016-04-01	82.0
2016-07-01	83.2
2016-10-01	82.7
2017-01-01	82.9
2017-04-01	83.7
2017-07-01	83.1
2017-10-01	83.1
2018-01-01	83.8
2018-04-01	84.4