Quarter	Percent
1999-04-01	72.4
2000-04-01	72.7
2001-04-01	72.6
2002-04-01	71.8
2003-04-01	70.9
2004-04-01	70
2005-01-01	70.3
2005-04-01	71.1
2005-07-01	71.8
2005-10-01	71.8
2006-01-01	71.4
2006-04-01	72.5
2006-07-01	73.5
2006-10-01	73.7
2007-01-01	73.6
2007-04-01	74.4
2007-07-01	75.3
2007-10-01	75.3
2008-01-01	75
2008-04-01	75.5
2008-07-01	76.7
2008-10-01	76.2
2009-01-01	75
2009-04-01	75.1
2009-07-01	75.6
2009-10-01	75.9
2010-01-01	75.3
2010-04-01	76.1
2010-07-01	76.7
2010-10-01	76.9
2011-01-01	76.5
2011-04-01	77.4
2011-07-01	77.9
2011-10-01	78.6
2012-01-01	77.1
2012-04-01	77.7
2012-07-01	78.4
2012-10-01	78.4
2013-01-01	77.1
2013-04-01	78
2013-07-01	78.2
2013-10-01	78.5
2014-01-01	77.5
2014-04-01	77.6
2014-07-01	78.6
2014-10-01	78.5
2015-01-01	77.6
2015-04-01	77.3
2015-07-01	78.3
2015-10-01	78.7
2016-01-01	77.8
2016-04-01	78.0
2016-07-01	78.9
2016-10-01	79.0
2017-01-01	78.1
2017-04-01	78.6
2017-07-01	79.3
2017-10-01	79.6
2018-01-01	79.1
2018-04-01	79.2