Quarter	Percent
1998-04-01	59.5
1998-10-01	61.0
1999-04-01	59.8
1999-10-01	58.8
2000-04-01	57.2
2000-10-01	56.0
2001-04-01	56.7
2001-10-01	57.5
2002-01-01	57.5
2002-04-01	58.5
2002-07-01	61.8
2002-10-01	59.4
2003-01-01	60.0
2003-04-01	59.4
2003-07-01	61.1
2003-10-01	60.1
2004-01-01	59.4
2004-04-01	60.8
2004-07-01	61.0
2004-10-01	60.2
2005-01-01	61.0
2005-04-01	60.8
2005-07-01	62.9
2005-10-01	62.1
2006-01-01	64.4
2006-04-01	63.7
2006-07-01	68.3
2006-10-01	66.1
2007-01-01	65.3
2007-04-01	67.1
2007-07-01	69.9
2007-10-01	69.0
2008-01-01	67.6
2008-04-01	68.3
2008-07-01	67.7
2008-10-01	64.6
2009-01-01	59.7
2009-04-01	56.8
2009-07-01	54.8
2009-10-01	52.2
2010-01-01	50.5
2010-04-01	52.2
2010-07-01	54.5
2010-10-01	55.0
2011-01-01	54.6
2011-04-01	55.5
2011-07-01	57.1
2011-10-01	57.7
2012-01-01	57.0
2012-04-01	58.4
2012-07-01	60.9
2012-10-01	60.3
2013-01-01	60.1
2013-04-01	60.5
2013-07-01	62.7
2013-10-01	62.9
2014-01-01	61.2
2014-04-01	62.2
2014-07-01	63.4
2014-10-01	64.2
2015-01-01	63.6
2015-04-01	64.1
2015-07-01	64.5
2015-10-01	65.2
2016-01-01	64.1
2016-04-01	64.7
2016-07-01	64.8
2016-10-01	64.0
2017-01-01	64.6
2017-04-01	65.3
2017-07-01	67.0
2017-10-01	67.2
2018-01-01	66.7
2018-04-01	67.0