Quarter	Percent
1999-04-01	66.2
1999-07-01	68.8
1999-10-01	67.7
2000-01-01	67.6
2000-04-01	68.1
2000-07-01	70
2000-10-01	68.4
2001-01-01	68.3
2001-04-01	68.5
2001-07-01	70.2
2001-10-01	68.5
2002-01-01	67.6
2002-04-01	67.5
2002-07-01	68.9
2002-10-01	67.6
2003-01-01	67.1
2003-04-01	67.2
2003-07-01	68.3
2003-10-01	67.7
2004-01-01	67.8
2004-04-01	67.5
2004-07-01	69.2
2004-10-01	68.2
2005-01-01	68.2
2005-04-01	68.5
2005-07-01	70.2
2005-10-01	69.2
2006-01-01	69.5
2006-04-01	69.7
2006-07-01	70.9
2006-10-01	70.2
2007-01-01	72.5
2007-04-01	72.6
2007-07-01	73.3
2007-10-01	71.9
2008-01-01	70.7
2008-04-01	70.4
2008-07-01	69.8
2008-10-01	67.1
2009-01-01	63.1
2009-04-01	61.8
2009-07-01	61.0
2009-10-01	59.6
2010-01-01	58.4
2010-04-01	58.6
2010-07-01	58.6
2010-10-01	57.2
2011-01-01	56.7
2011-04-01	57.2
2011-07-01	57.1
2011-10-01	57.0
2012-01-01	56.0
2012-04-01	56.4
2012-07-01	57.0
2012-10-01	57.0
2013-01-01	57.2
2013-04-01	58.2
2013-07-01	59.4
2013-10-01	59.9
2014-01-01	59.1
2014-04-01	59.6
2014-07-01	60.7
2014-10-01	61.0
2015-01-01	60.7
2015-04-01	61.7
2015-07-01	62.5
2015-10-01	61.8
2016-01-01	61.5
2016-04-01	62.7
2016-07-01	63.6
2016-10-01	63.4
2017-01-01	62.9
2017-04-01	63.3
2017-07-01	64.3
2017-10-01	64.3
2018-01-01	64.3
2018-04-01	64.3