Quarter	Percent
1999-04-01	62.7
2000-01-01	66.4
2000-04-01	68.4
2000-07-01	69.9
2000-10-01	70.2
2001-01-01	69.3
2001-04-01	70.4
2001-07-01	72
2001-10-01	69.9
2002-01-01	68.7
2002-04-01	70.5
2002-07-01	71.2
2002-10-01	69.8
2003-01-01	68.2
2003-04-01	68.7
2003-07-01	69.4
2003-10-01	67.1
2004-01-01	65.5
2004-04-01	66.2
2004-07-01	66.7
2004-10-01	65
2005-01-01	64
2005-04-01	65.2
2005-07-01	66.4
2005-10-01	65.2
2006-01-01	64.5
2006-04-01	66.2
2006-07-01	67.4
2006-10-01	66.6
2007-01-01	66.3
2007-04-01	68.6
2007-07-01	70.4
2007-10-01	68.4
2008-01-01	68
2008-04-01	69.3
2008-07-01	70.5
2008-10-01	69.4
2009-01-01	68.1
2009-04-01	68.4
2009-07-01	68.7
2009-10-01	66.6
2010-01-01	62
2010-04-01	63.2
2010-07-01	64.3
2010-10-01	62.6
2011-01-01	59.4
2011-04-01	61.1
2011-07-01	62.8
2011-10-01	61.8
2012-01-01	60.1
2012-04-01	61.0
2012-07-01	62.4
2012-10-01	61.0
2013-01-01	59.3
2013-04-01	60.5
2013-07-01	61.0
2013-10-01	59.5
2014-01-01	57.2
2014-04-01	58.4
2014-07-01	60.1
2014-10-01	59.5
2015-01-01	59.5
2015-04-01	61.3
2015-07-01	62.0
2015-10-01	60.2
2016-01-01	59.1
2016-04-01	61.1
2016-07-01	62.3
2016-10-01	60.8
2017-01-01	60.1
2017-04-01	61.9
2017-07-01	64.0
2017-10-01	63.1
2018-01-01	62.4
2018-04-01	63.9