Quarter	Percent
1998-01-01	70.3
1998-04-01	71.0
1998-07-01	70.7
1998-10-01	70.6
1999-01-01	70.4
1999-04-01	70.3
1999-07-01	70.6
1999-10-01	70.7
2000-01-01	70.9
2000-04-01	71
2000-07-01	71.5
2000-10-01	71.7
2001-01-01	71.7
2001-04-01	71.8
2001-07-01	71.9
2001-10-01	71.8
2002-01-01	71.7
2002-04-01	71.6
2002-07-01	71.4
2002-10-01	70.4
2003-01-01	69.8
2003-04-01	69.9
2003-07-01	70.1
2003-10-01	69.7
2004-01-01	69.4
2004-04-01	69.3
2004-07-01	68.9
2004-10-01	68.5
2005-01-01	68.2
2005-04-01	68.3
2005-07-01	68.3
2005-10-01	68.2
2006-01-01	68.5
2006-04-01	68.9
2006-07-01	68.9
2006-10-01	68.3
2007-01-01	68.3
2007-04-01	68.4
2007-07-01	68.8
2007-10-01	68.8
2008-01-01	68.8
2008-04-01	68.8
2008-07-01	68.4
2008-10-01	68.1
2009-01-01	66.6
2009-04-01	66.3
2009-07-01	65.2
2009-10-01	65
2010-01-01	65
2010-04-01	64.6
2010-07-01	64.6
2010-10-01	64.4
2011-01-01	63.3
2011-04-01	63.4
2011-07-01	63.5
2011-10-01	61.4
2012-01-01	60.6
2012-04-01	60.6
2012-07-01	60
2012-10-01	58.7
2013-01-01	57.5
2013-04-01	58.5
2013-07-01	59.4
2013-10-01	59.7
2014-01-01	59.1
2014-04-01	60.4
2014-07-01	61.3
2014-10-01	60.3
2015-01-01	60.0
2015-04-01	61.0
2015-07-01	61.4
2015-10-01	61.6
2016-01-01	60.5
2016-04-01	62.2
2016-07-01	63.1
2016-10-01	62.6
2017-01-01	63.0
2017-04-01	64.4
2017-07-01	65.1
2017-10-01	65.1
2018-01-01	64.9
2018-04-01	65.6