Quarter	Percent
1999-01-01	75.4
2000-01-01	75.2
2001-01-01	75.1
2002-01-01	75.5
2003-01-01	75.5
2003-04-01	75.3
2003-07-01	75.8
2003-10-01	75.8
2004-01-01	75.5
2004-04-01	75.3
2004-07-01	75.7
2004-10-01	75.3
2005-01-01	75.0
2005-04-01	75.1
2005-07-01	75.5
2005-10-01	75.1
2006-01-01	74.7
2006-04-01	74.8
2006-07-01	75.4
2006-10-01	74.6
2007-01-01	74.5
2007-04-01	74.5
2007-07-01	75.2
2007-10-01	74.5
2008-01-01	74.4
2008-04-01	74.5
2008-07-01	75.0
2008-10-01	75.0
2009-01-01	74.9
2009-04-01	75.1
2009-07-01	74.8
2009-10-01	75
2010-01-01	74.9
2010-04-01	74.8
2010-07-01	74.9
2010-10-01	74.7
2011-01-01	74.5
2011-04-01	74.6
2011-07-01	74.7
2011-10-01	74.7
2012-01-01	74.8
2012-04-01	75.1
2012-07-01	75.4
2012-10-01	75.8
2013-01-01	75.5
2013-04-01	75.6
2013-07-01	75.6
2013-10-01	75.2
2014-01-01	75.1
2014-04-01	75.0
2014-07-01	75.0
2014-10-01	75.3
2015-01-01	75.1
2015-04-01	75.3
2015-07-01	75.4
2015-10-01	75.4
2016-01-01	75.4
2016-04-01	75.3
2016-07-01	75.3
2016-10-01	75.6
2017-01-01	74.9
2017-04-01	75.7
2017-07-01	76.0
2017-10-01	75.9
2018-01-01	75.6
2018-04-01	75.7