Quarter	Percent
1999-04-01	74.4
2000-04-01	75
2001-04-01	74.9
2002-04-01	75.5
2003-01-01	73.3
2003-04-01	73.3
2003-07-01	73.3
2003-10-01	73.3
2004-01-01	72.8
2004-04-01	72.8
2004-07-01	72.8
2004-10-01	72.8
2005-01-01	73.3
2005-04-01	73.3
2005-07-01	73.3
2005-10-01	73.3
2006-01-01	72.6
2006-04-01	72.6
2006-07-01	72.6
2006-10-01	72.6
2007-01-01	72.2
2007-04-01	72.8
2007-07-01	73.4
2007-10-01	71
2008-01-01	70.8
2008-04-01	72.8
2008-07-01	72.5
2008-10-01	69.8
2009-01-01	71.5
2009-04-01	74.6
2009-07-01	73.8
2009-10-01	72.8
2010-01-01	72.3
2010-04-01	72.2
2010-07-01	74.7
2010-10-01	73.3
2011-01-01	73.6
2011-04-01	71.1
2011-07-01	72.3
2011-10-01	71.2
2012-01-01	71.2
2012-04-01	72.8
2012-07-01	72.7
2012-10-01	73.1
2013-01-01	71.3
2013-04-01	70.7
2013-07-01	73.3
2013-10-01	73.3
2014-01-01	71
2014-04-01	73
2014-07-01	72.5
2014-10-01	73.9
2015-01-01	71.3
2015-04-01	72.2
2015-07-01	71.2
2015-10-01	70.5
2016-01-01	70.7
2016-04-01	70.8
2016-07-01	69.7
2016-10-01	70.9
2017-01-01	69.5
2017-04-01	69.7
2017-07-01	70.1
2017-10-01	70.4
2018-01-01	70.7
2018-04-01	69.7