Quarter	Percent
1999-04-01	77.2
2000-01-01	74.6
2000-04-01	73.6
2000-07-01	73
2000-10-01	72.1
2001-01-01	71.8
2001-04-01	71.7
2001-07-01	71.5
2001-10-01	71.3
2002-01-01	70.3
2002-04-01	70.6
2002-07-01	68.4
2002-10-01	68.3
2003-01-01	67.6
2003-04-01	67.4
2003-07-01	67.2
2003-10-01	67.5
2004-01-01	66.4
2004-04-01	66.4
2004-07-01	65.1
2004-10-01	64.5
2005-01-01	64
2005-04-01	63.7
2005-07-01	63.5
2005-10-01	62.9
2006-01-01	62.5
2006-04-01	62
2006-07-01	61
2006-10-01	60.3
2007-01-01	59.9
2007-04-01	58.5
2007-07-01	58
2007-10-01	58
2008-01-01	57.5
2008-04-01	56.6
2008-07-01	56.2
2008-10-01	55.7
2009-01-01	54.1
2009-04-01	54.8
2009-07-01	53.7
2009-10-01	53.4
2010-01-01	56.2
2010-04-01	56.1
2010-07-01	55.5
2010-10-01	54.3
2011-01-01	53.1
2011-04-01	52.5
2011-07-01	51.5
2011-10-01	50
2012-01-01	50.1
2012-04-01	49.2
2012-07-01	49.0
2012-10-01	47.8
2013-01-01	47.8
2013-04-01	47.3
2013-07-01	47.0
2013-10-01	46.8
2014-01-01	46.5
2014-04-01	46
2014-07-01	45.1
2014-10-01	45.1
2015-01-01	44.5
2015-04-01	43.1
2015-07-01	42.8
2015-10-01	42.9
2016-01-01	42.1
2016-04-01	41.3
2016-07-01	41.0
2016-10-01	41.3
2017-01-01	40.7
2017-04-01	39.6
2017-07-01	39.8
2017-10-01	39.4
2018-01-01	39.1
2018-04-01	38.2