Quarter	Percent
1999-04-01	62.9
1999-07-01	62.8
1999-10-01	63.6
2000-01-01	64
2000-04-01	64.9
2000-07-01	64.6
2000-10-01	65.2
2001-01-01	65.3
2001-04-01	66
2001-07-01	66.3
2001-10-01	66.6
2002-01-01	67.1
2002-04-01	67.6
2002-07-01	66.5
2002-10-01	66.6
2003-01-01	67
2003-04-01	67.2
2003-07-01	67
2003-10-01	67.5
2004-01-01	67.6
2004-04-01	68
2004-07-01	67.8
2004-10-01	68.5
2005-01-01	69.2
2005-04-01	69.6
2005-07-01	69.7
2005-10-01	69.9
2006-01-01	70.3
2006-04-01	70.2
2006-07-01	70.5
2006-10-01	70.9
2007-01-01	72.2
2007-04-01	72.5
2007-07-01	72.5
2007-10-01	72.2
2008-01-01	72.6
2008-04-01	72.2
2008-07-01	72.4
2008-10-01	72.7
2009-01-01	72.1
2009-04-01	72.5
2009-07-01	73.2
2009-10-01	72.5
2010-01-01	72.6
2010-04-01	72.9
2010-07-01	72.4
2010-10-01	72.3
2011-01-01	72.0
2011-04-01	72.9
2011-07-01	72.9
2011-10-01	72.9
2012-01-01	73.0
2012-04-01	72.8
2012-07-01	72.9
2012-10-01	73.1
2013-01-01	73.5
2013-04-01	74.3
2013-07-01	74.1
2013-10-01	74.2
2014-01-01	74.3
2014-04-01	74.1
2014-07-01	74.4
2014-10-01	74.2
2015-01-01	74.0
2015-04-01	74.8
2015-07-01	74.2
2015-10-01	75.0
2016-01-01	74.6
2016-04-01	74.9
2016-07-01	74.9
2016-10-01	74.6
2017-01-01	75.1
2017-04-01	74.7
2017-07-01	76.6
2017-10-01	76.7
2018-01-01	76.3
2018-04-01	76.9