Quarter	Percent
1998-04-01	62.7
1999-04-01	64.6
2000-04-01	64.3
2001-01-01	65.8
2001-04-01	66.2
2001-07-01	67.3
2001-10-01	67.5
2002-01-01	67.4
2002-04-01	68.3
2002-07-01	68.2
2002-10-01	68.2
2003-01-01	67.9
2003-04-01	68.6
2003-07-01	69
2003-10-01	68.7
2004-01-01	68.5
2004-04-01	69
2004-07-01	69.5
2004-10-01	69.5
2005-01-01	69.4
2005-04-01	68.9
2005-07-01	69.7
2005-10-01	70.1
2006-01-01	70.3
2006-04-01	69.5
2006-07-01	69.3
2006-10-01	69.4
2007-01-01	69.1
2007-04-01	69.9
2007-07-01	70.6
2007-10-01	70.2
2008-01-01	69.6
2008-04-01	70.4
2008-07-01	70.3
2008-10-01	70
2009-01-01	69.8
2009-04-01	69.6
2009-07-01	70
2009-10-01	70.5
2010-01-01	69.9
2010-04-01	70.2
2010-07-01	70.8
2010-10-01	71
2011-01-01	71.2
2011-04-01	72.2
2011-07-01	72.1
2011-10-01	72.6
2012-01-01	72.1
2012-04-01	73
2012-07-01	73.2
2012-10-01	73.5
2013-01-01	72.7
2013-04-01	73.3
2013-07-01	73.9
2013-10-01	74.4
2014-01-01	73.5
2014-04-01	74.4
2014-07-01	74
2014-10-01	74
2015-01-01	74.1
2015-04-01	74.4
2015-07-01	74.4
2015-10-01	74.9
2016-01-01	74.5
2016-04-01	75.5
2016-07-01	76.1
2016-10-01	75.8
2017-01-01	75.8
2017-04-01	76.7
2017-07-01	76.8
2017-10-01	76.4
2018-01-01	77.2
2018-04-01	77.7