Quarter	Percent
1998-04-01	68.8
1999-04-01	69.6
2000-04-01	69.3
2001-04-01	70.6
2002-04-01	71.5
2003-04-01	70.7
2004-04-01	70.3
2005-04-01	70.4
2006-04-01	71.1
2007-04-01	71.6
2008-04-01	73.5
2009-04-01	73.6
2010-01-01	71.2
2010-04-01	71.0
2010-07-01	71.3
2010-10-01	71.7
2011-01-01	72.3
2011-04-01	72.9
2011-07-01	72.0
2011-10-01	73.0
2012-01-01	73.0
2012-04-01	72.9
2012-07-01	73.3
2012-10-01	72.8
2013-01-01	72.9
2013-04-01	73.1
2013-07-01	73.1
2013-10-01	73.7
2014-01-01	73.2
2014-04-01	74.0
2014-07-01	73.7
2014-10-01	75.4
2015-01-01	74.9
2015-04-01	74.6
2015-07-01	74.1
2015-10-01	75.2
2016-01-01	75.9
2016-04-01	75.2
2016-07-01	74.8
2016-10-01	75.8
2017-01-01	75.3
2017-04-01	74.8
2017-07-01	75.0
2017-10-01	75.7
2018-01-01	75.3
2018-04-01	75.0