Quarter	Percent
1999-04-01	80.9
2000-04-01	82.2
2001-04-01	81.9
2002-04-01	80.3
2003-01-01	76.7
2003-04-01	79.8
2003-07-01	80.9
2003-10-01	77.1
2004-01-01	76.3
2004-04-01	78.6
2004-07-01	79
2004-10-01	77.3
2005-01-01	77
2005-04-01	80.5
2005-07-01	80.8
2005-10-01	78.8
2006-01-01	78.8
2006-04-01	81
2006-07-01	81.2
2006-10-01	79.5
2007-01-01	80.1
2007-04-01	81.6
2007-07-01	81.5
2007-10-01	79.9
2008-01-01	78.7
2008-04-01	81
2008-07-01	80.5
2008-10-01	77.8
2009-01-01	73.4
2009-04-01	73.9
2009-07-01	76.3
2009-10-01	74.6
2010-01-01	73.3
2010-04-01	75.1
2010-07-01	75.1
2010-10-01	73.7
2011-01-01	72.5
2011-04-01	75.4
2011-07-01	75.4
2011-10-01	73.5
2012-01-01	73
2012-04-01	76.1
2012-07-01	76.4
2012-10-01	74.8
2013-01-01	73.8
2013-04-01	76.9
2013-07-01	78.4
2013-10-01	76.3
2014-01-01	75.4
2014-04-01	78.9
2014-07-01	79.8
2014-10-01	78.4
2015-01-01	78.1
2015-04-01	80.6
2015-07-01	80.8
2015-10-01	79.3
2016-01-01	79.5
2016-04-01	82.1
2016-07-01	82.6
2016-10-01	81.0
2017-01-01	80.8
2017-04-01	81.8
2017-07-01	80.4
2017-10-01	79.4
2018-01-01	78.7
2018-04-01	80.2