Quarter	Percent
1999-04-01	66.8
1999-07-01	71.3
1999-10-01	69.2
2000-01-01	66.9
2000-04-01	67
2000-07-01	70.4
2000-10-01	67.6
2001-01-01	66.7
2001-04-01	65.7
2001-07-01	70.9
2001-10-01	68.5
2002-01-01	66.3
2002-04-01	65.5
2002-07-01	68.5
2002-10-01	67.3
2003-01-01	65.9
2003-04-01	64
2003-07-01	68.4
2003-10-01	66.8
2004-01-01	65.0
2004-04-01	64.0
2004-07-01	68
2004-10-01	66
2005-01-01	64.8
2005-04-01	63.2
2005-07-01	67.1
2005-10-01	65.6
2006-01-01	63.2
2006-04-01	63.1
2006-07-01	68.3
2006-10-01	64.9
2007-01-01	63.4
2007-04-01	62.4
2007-07-01	66.1
2007-10-01	64.7
2008-01-01	62.8
2008-04-01	62.6
2008-07-01	67.1
2008-10-01	64.8
2009-01-01	61.1
2009-04-01	60.7
2009-07-01	63.4
2009-10-01	60.1
2010-01-01	58.2
2010-04-01	59.6
2010-07-01	64.1
2010-10-01	61.8
2011-01-01	58.4
2011-04-01	59.5
2011-07-01	63.5
2011-10-01	61.5
2012-01-01	59.4
2012-04-01	60.3
2012-07-01	63
2012-10-01	61.1
2013-01-01	58.4
2013-04-01	58.8
2013-07-01	63.0
2013-10-01	60.7
2014-01-01	58.4
2014-04-01	58.3
2014-07-01	61.3
2014-10-01	60.0
2015-01-01	58.8
2015-04-01	58.2
2015-07-01	62.1
2015-10-01	60.8
2016-01-01	59.0
2016-04-01	58.2
2016-07-01	60.5
2016-10-01	59.5
2017-01-01	57.8
2017-04-01	57.7
2017-07-01	59.1
2017-10-01	58.8
2018-01-01	58.1
2018-04-01	57.6