Quarter	Percent
1998-04-01	63.2
1999-04-01	65.8
2000-04-01	64.6
2001-01-01	66.5
2001-04-01	66.1
2001-07-01	67.2
2001-10-01	67.7
2002-01-01	68
2002-04-01	68.3
2002-07-01	68.1
2002-10-01	68.4
2003-01-01	68.7
2003-04-01	68.7
2003-07-01	69.1
2003-10-01	69.1
2004-01-01	69.1
2004-04-01	69.6
2004-07-01	69.9
2004-10-01	70.3
2005-01-01	69.7
2005-04-01	68
2005-07-01	68.4
2005-10-01	70
2006-01-01	70.7
2006-04-01	69.5
2006-07-01	68.9
2006-10-01	69.2
2007-01-01	69.1
2007-04-01	69.5
2007-07-01	69.9
2007-10-01	69.2
2008-01-01	68.5
2008-04-01	68.8
2008-07-01	69.4
2008-10-01	69.5
2009-01-01	70.1
2009-04-01	69.9
2009-07-01	69.7
2009-10-01	70.1
2010-01-01	70.1
2010-04-01	69.8
2010-07-01	70.2
2010-10-01	70.9
2011-01-01	72.2
2011-04-01	72
2011-07-01	71.8
2011-10-01	72.4
2012-01-01	72.2
2012-04-01	73.1
2012-07-01	73.1
2012-10-01	73.7
2013-01-01	73.1
2013-04-01	73.1
2013-07-01	73.1
2013-10-01	74.1
2014-01-01	74.5
2014-04-01	75.3
2014-07-01	75.2
2014-10-01	74.6
2015-01-01	75.2
2015-04-01	75.4
2015-07-01	75.5
2015-10-01	76.0
2016-01-01	76.0
2016-04-01	76.9
2016-07-01	77.1
2016-10-01	77.4
2017-01-01	77.8
2017-04-01	78.1
2017-07-01	78.1
2017-10-01	77.3
2018-01-01	78.0
2018-04-01	78.4