Quarter	Percent
1999-01-01	78.8
1999-04-01	78.8
1999-07-01	78.8
1999-10-01	78.9
2000-01-01	78.4
2000-04-01	77.5
2000-07-01	77
2000-10-01	76.4
2001-01-01	76.6
2001-04-01	76.7
2001-07-01	76.2
2001-10-01	75.8
2002-01-01	75.5
2002-04-01	74.9
2002-07-01	75.3
2002-10-01	74.9
2003-01-01	74.7
2003-04-01	73.9
2003-07-01	73.5
2003-10-01	73.2
2004-01-01	72.7
2004-04-01	72.4
2004-07-01	72.5
2004-10-01	72.2
2005-01-01	70.5
2005-04-01	70
2005-07-01	70.5
2005-10-01	69.4
2006-01-01	68.5
2006-04-01	69
2006-07-01	69.7
2006-10-01	68.2
2007-01-01	67.3
2007-04-01	67.1
2007-07-01	67.8
2007-10-01	66.8
2008-01-01	66.3
2008-04-01	66
2008-07-01	66.1
2008-10-01	64.6
2009-01-01	63.8
2009-04-01	62.5
2009-07-01	63
2009-10-01	62.5
2010-01-01	61.9
2010-04-01	62.3
2010-07-01	61.5
2010-10-01	60.5
2011-01-01	59.8
2011-04-01	58.2
2011-07-01	57.4
2011-10-01	57.5
2012-01-01	57.2
2012-04-01	55.8
2012-07-01	55.5
2012-10-01	56
2013-01-01	55.4
2013-04-01	55
2013-07-01	54.8
2013-10-01	54
2014-01-01	53.6
2014-04-01	53.1
2014-07-01	53.5
2014-10-01	52.2
2015-01-01	51.7
2015-04-01	51.0
2015-07-01	50.8
2015-10-01	48.9
2016-01-01	48.5
2016-04-01	48.6
2016-07-01	48.0
2016-10-01	48.1
2017-01-01	48.4
2017-04-01	48.0
2017-07-01	48.5
2017-10-01	47.9
2018-01-01	47.3
2018-04-01	47.2
2018-07-01	47.5