Quarter	Percent
1999-04-01	82.2
2000-04-01	75.7
2001-04-01	78.7
2002-04-01	83.8
2003-01-01	79.8
2003-04-01	79.8
2003-07-01	79.2
2003-10-01	76.6
2004-01-01	79
2004-04-01	73.8
2004-07-01	75.1
2004-10-01	78.6
2005-01-01	77.9
2005-04-01	78.7
2005-07-01	78.1
2005-10-01	83.8
2006-01-01	79.8
2006-04-01	80
2006-07-01	80.1
2006-10-01	79.2
2007-01-01	82
2007-04-01	78.1
2007-07-01	78.7
2007-10-01	80.6
2008-01-01	78
2008-04-01	81.5
2008-07-01	75.1
2008-10-01	74.2
2009-01-01	74.4
2009-04-01	73.7
2009-07-01	76.7
2009-10-01	79.1
2010-01-01	75.7
2010-04-01	74.7
2010-07-01	78.4
2010-10-01	76.7
2011-01-01	75.3
2011-04-01	73.4
2011-07-01	78.6
2011-10-01	77.9
2012-01-01	74.5
2012-04-01	74.4
2012-07-01	76.2
2012-10-01	74.9
2013-01-01	74
2013-04-01	75.6
2013-07-01	76.1
2013-10-01	74.5
2014-01-01	78.2
2014-04-01	80.7
2014-07-01	82.4
2014-10-01	82.0
2015-01-01	81.5
2015-04-01	79.3
2015-07-01	82.2
2015-10-01	79.0
2016-01-01	81.7
2016-04-01	77.7
2016-07-01	79.2
2016-10-01	79.0
2017-01-01	79.5
2017-04-01	79.4
2017-07-01	79.1
2017-10-01	76.6
2018-01-01	74.4
2018-04-01	74.6