Quarter	Percent
1998-04-01	58.1
1999-04-01	60.4
2000-04-01	61.7
2001-01-01	63
2001-04-01	64.5
2001-07-01	65.2
2001-10-01	63.9
2002-01-01	63.5
2002-04-01	64.4
2002-07-01	65.1
2002-10-01	63.7
2003-01-01	63.2
2003-04-01	64.3
2003-07-01	64.3
2003-10-01	62.8
2004-01-01	62.1
2004-04-01	63.1
2004-07-01	63.8
2004-10-01	62.2
2005-01-01	61.3
2005-04-01	62.7
2005-07-01	63.3
2005-10-01	62.5
2006-01-01	61.6
2006-04-01	62.9
2006-07-01	64.4
2006-10-01	63
2007-01-01	62.6
2007-04-01	64.1
2007-07-01	65.2
2007-10-01	63.7
2008-01-01	63.1
2008-04-01	64.4
2008-07-01	64.8
2008-10-01	63.1
2009-01-01	62.1
2009-04-01	62.9
2009-07-01	62.8
2009-10-01	61.2
2010-01-01	60.3
2010-04-01	61.6
2010-07-01	62.4
2010-10-01	61.1
2011-01-01	61.4
2011-04-01	62.9
2011-07-01	63.6
2011-10-01	62.5
2012-01-01	62.1
2012-04-01	63.4
2012-07-01	63.9
2012-10-01	62.6
2013-01-01	62.1
2013-04-01	63.7
2013-07-01	64.1
2013-10-01	63.2
2014-01-01	62.5
2014-04-01	64
2014-07-01	65.2
2014-10-01	63.4
2015-01-01	63.2
2015-04-01	64.5
2015-07-01	65.7
2015-10-01	64.4
2016-01-01	64.1
2016-04-01	65.6
2016-07-01	65.8
2016-10-01	64.8
2017-01-01	64.9
2017-04-01	65.9
2017-07-01	66.5
2017-10-01	65.4
2018-01-01	65.2
2018-04-01	66.7