Quarter	Percent
1998-04-01	65.7
1999-04-01	67.3
2000-04-01	67
2001-01-01	68.5
2001-04-01	68.9
2001-07-01	69.9
2001-10-01	70.2
2002-01-01	69.5
2002-04-01	70.8
2002-07-01	70.8
2002-10-01	70.5
2003-01-01	69.9
2003-04-01	70.9
2003-07-01	71.4
2003-10-01	70.8
2004-01-01	70.6
2004-04-01	71.1
2004-07-01	71.9
2004-10-01	71.3
2005-01-01	71.9
2005-04-01	71.8
2005-07-01	73.1
2005-10-01	72.7
2006-01-01	72.6
2006-04-01	72.3
2006-07-01	72.3
2006-10-01	72.1
2007-01-01	71.9
2007-04-01	72.8
2007-07-01	73.5
2007-10-01	73.4
2008-01-01	73.2
2008-04-01	73.9
2008-07-01	73.5
2008-10-01	73
2009-01-01	72.6
2009-04-01	72.6
2009-07-01	73.6
2009-10-01	74.1
2010-01-01	73.1
2010-04-01	73.8
2010-07-01	74.6
2010-10-01	74.6
2011-01-01	73.9
2011-04-01	75.5
2011-07-01	75.4
2011-10-01	75.9
2012-01-01	75.4
2012-04-01	76.4
2012-07-01	76.6
2012-10-01	76.7
2013-01-01	75.9
2013-04-01	76.6
2013-07-01	77.4
2013-10-01	77.6
2014-01-01	75.7
2014-04-01	77
2014-07-01	76.3
2014-10-01	76.8
2015-01-01	76.5
2015-04-01	76.8
2015-07-01	76.7
2015-10-01	77.3
2016-01-01	76.7
2016-04-01	77.0
2016-07-01	78.4
2016-10-01	77.7
2017-01-01	77.3
2017-04-01	78.9
2017-07-01	78.8
2017-10-01	78.6
2018-01-01	79.1
2018-04-01	80.0