Quarter	Percent
1999-04-01	70.1
2000-01-01	71.5
2000-04-01	71.9
2000-07-01	70.7
2000-10-01	71.6
2001-01-01	71.1
2001-04-01	71
2001-07-01	70.9
2001-10-01	70
2002-01-01	70.2
2002-04-01	70.8
2002-07-01	70.6
2002-10-01	71.2
2003-01-01	71.1
2003-04-01	71
2003-07-01	72.1
2003-10-01	71.9
2004-01-01	70.7
2004-04-01	71.1
2004-07-01	71.1
2004-10-01	71
2005-01-01	70.6
2005-04-01	70.2
2005-07-01	70.9
2005-10-01	71.4
2006-01-01	72.3
2006-04-01	73.2
2006-07-01	73
2006-10-01	73.9
2007-01-01	73.6
2007-04-01	73.5
2007-07-01	73.8
2007-10-01	74.5
2008-01-01	74.3
2008-04-01	74.1
2008-07-01	74.2
2008-10-01	74
2009-01-01	72.6
2009-04-01	73.3
2009-07-01	72.3
2009-10-01	72.9
2010-01-01	72.3
2010-04-01	72.6
2010-07-01	71.9
2010-10-01	72
2011-01-01	71.6
2011-04-01	72
2011-07-01	74.1
2011-10-01	74
2012-01-01	74.2
2012-04-01	74.7
2012-07-01	74.8
2012-10-01	75.3
2013-01-01	74.2
2013-04-01	75.7
2013-07-01	75.4
2013-10-01	74.3
2014-01-01	74.9
2014-04-01	75.4
2014-07-01	75.9
2014-10-01	77.1
2015-01-01	75.8
2015-04-01	75.5
2015-07-01	75.7
2015-10-01	75.3
2016-01-01	75.7
2016-04-01	76.1
2016-07-01	75.7
2016-10-01	75.4
2017-01-01	74.4
2017-04-01	75.5
2017-07-01	75.2
2017-10-01	74.9
2018-01-01	77.3
2018-04-01	76.0