Quarter	Percent
1999-04-01	58.9
2000-01-01	57.7
2000-04-01	59.3
2000-07-01	58.9
2000-10-01	59.8
2001-01-01	60.5
2001-04-01	60.9
2001-07-01	60.8
2001-10-01	61.5
2002-01-01	60.7
2002-04-01	63.1
2002-07-01	62.1
2002-10-01	61.2
2003-01-01	62.7
2003-04-01	61.6
2003-07-01	62.2
2003-10-01	62.6
2004-01-01	60.4
2004-04-01	61.1
2004-07-01	60.4
2004-10-01	60.6
2005-01-01	60.2
2005-04-01	59.4
2005-07-01	60.5
2005-10-01	60.4
2006-01-01	61.1
2006-04-01	61.2
2006-07-01	62
2006-10-01	62.1
2007-01-01	62.6
2007-04-01	64.2
2007-07-01	64.3
2007-10-01	64.7
2008-01-01	63.9
2008-04-01	64.4
2008-07-01	64
2008-10-01	64.4
2009-01-01	64.1
2009-04-01	64.7
2009-07-01	64.7
2009-10-01	65.1
2010-01-01	64.4
2010-04-01	65.5
2010-07-01	64.3
2010-10-01	65.6
2011-01-01	65.3
2011-04-01	66.6
2011-07-01	66.3
2011-10-01	66.3
2012-01-01	66.4
2012-04-01	67.2
2012-07-01	67
2012-10-01	67
2013-01-01	66
2013-04-01	67.6
2013-07-01	67.4
2013-10-01	67.5
2014-01-01	67.4
2014-04-01	68
2014-07-01	68.9
2014-10-01	69.7
2015-01-01	68.0
2015-04-01	69.3
2015-07-01	68.9
2015-10-01	68.8
2016-01-01	69.1
2016-04-01	69.6
2016-07-01	69.6
2016-10-01	69.7
2017-01-01	69.2
2017-04-01	68.8
2017-07-01	68.5
2017-10-01	68.4
2018-01-01	67.3
2018-04-01	68.5