Quarter	Percent
1999-01-01	65
2000-01-01	68.7
2000-04-01	67.9
2000-07-01	67.8
2000-10-01	70.2
2001-01-01	71.5
2001-04-01	68.4
2001-07-01	68.7
2001-10-01	70.7
2002-01-01	71.1
2002-04-01	70.3
2002-07-01	71.1
2002-10-01	71
2003-01-01	70.6
2003-04-01	69.7
2003-07-01	69.5
2003-10-01	69.6
2004-01-01	71.2
2004-04-01	70.7
2004-07-01	69.8
2004-10-01	70
2005-01-01	71.3
2005-04-01	70.2
2005-07-01	67.8
2005-10-01	68.7
2006-01-01	71
2006-04-01	70.2
2006-07-01	67.9
2006-10-01	68.4
2007-01-01	69.3
2007-04-01	68.8
2007-07-01	67.6
2007-10-01	67.1
2008-01-01	67.3
2008-04-01	66.7
2008-07-01	66.4
2008-10-01	66.2
2009-01-01	66.3
2009-04-01	66.1
2009-07-01	64.8
2009-10-01	64.9
2010-01-01	64.7
2010-04-01	64
2010-07-01	62.6
2010-10-01	62
2011-01-01	61.7
2011-04-01	60.6
2011-07-01	59.7
2011-10-01	59.5
2012-01-01	60
2012-04-01	58.4
2012-07-01	57.3
2012-10-01	57.2
2013-01-01	57.3
2013-04-01	56.4
2013-07-01	55.5
2013-10-01	54.9
2014-01-01	55.4
2014-04-01	55.2
2014-07-01	53.9
2014-10-01	53.3
2015-01-01	54.1
2015-04-01	54.6
2015-07-01	52.2
2015-10-01	51.6
2016-01-01	52.7
2016-04-01	52.7
2016-07-01	51.3
2016-10-01	50.1
2017-01-01	50.9
2017-04-01	49.8
2017-07-01	48.9
2017-10-01	49.9
2018-01-01	50.7
2018-04-01	49.4