Quarter	Percent
1998-04-01	78.5
1999-04-01	78.2
2000-04-01	77.8
2001-04-01	77.4
2002-04-01	76.7
2003-04-01	76.8
2004-04-01	76
2005-04-01	75.1
2006-04-01	75.4
2007-04-01	75.8
2008-04-01	75.5
2009-04-01	75.2
2010-01-01	73.9
2010-04-01	74.5
2010-07-01	74.8
2010-10-01	74.2
2011-01-01	74.5
2011-04-01	74.4
2011-07-01	75.0
2011-10-01	74.9
2012-01-01	74.0
2012-04-01	74.1
2012-07-01	75.1
2012-10-01	74.8
2013-01-01	74.3
2013-04-01	74.0
2013-07-01	74.1
2013-10-01	74.3
2014-01-01	73.9
2014-04-01	74.2
2014-07-01	74.2
2014-10-01	74.3
2015-01-01	74.2
2015-04-01	74.0
2015-07-01	74.1
2015-10-01	74.6
2016-01-01	74.3
2016-04-01	74.2
2016-07-01	74.7
2016-10-01	74.8
2017-01-01	74.0
2017-04-01	74.3
2017-07-01	74.8
2017-10-01	74.7
2018-01-01	73.9
2018-04-01	74.4