Quarter	Percent
1998-01-01	62.9
1998-04-01	64.1
1998-07-01	63.8
1998-10-01	62.0
1999-01-01	62.3
1999-04-01	62.0
1999-07-01	61.6
1999-10-01	60.6
2000-01-01	62.0
2000-04-01	62.2
2000-07-01	62.9
2000-10-01	62.0
2001-01-01	61.9
2001-04-01	62.3
2001-07-01	61.0
2001-10-01	61.5
2002-01-01	62.8
2002-04-01	63
2002-07-01	62.1
2002-10-01	60
2003-01-01	61.7
2003-04-01	62.4
2003-07-01	62.7
2003-10-01	61.8
2004-01-01	60.5
2004-04-01	59
2004-07-01	58
2004-10-01	58.9
2005-01-01	58.7
2005-04-01	58.6
2005-07-01	57.5
2005-10-01	57.7
2006-01-01	57.6
2006-04-01	57.9
2006-07-01	58.9
2006-10-01	58.3
2007-01-01	59.1
2007-04-01	57.8
2007-07-01	58.6
2007-10-01	59.1
2008-01-01	58.1
2008-04-01	58.2
2008-07-01	58.8
2008-10-01	58.3
2009-01-01	58.2
2009-04-01	57.5
2009-07-01	57
2009-10-01	57.1
2010-01-01	56.1
2010-04-01	55.9
2010-07-01	55.5
2010-10-01	55.8
2011-01-01	55.9
2011-04-01	54
2011-07-01	54.3
2011-10-01	52.6
2012-01-01	52.8
2012-04-01	52.2
2012-07-01	51.6
2012-10-01	50.1
2013-01-01	51.6
2013-04-01	53.4
2013-07-01	54.3
2013-10-01	54.8
2014-01-01	54.1
2014-04-01	54.6
2014-07-01	54.6
2014-10-01	53.8
2015-01-01	54.6
2015-04-01	56.6
2015-07-01	56.0
2015-10-01	56.6
2016-01-01	55.1
2016-04-01	58.9
2016-07-01	60.6
2016-10-01	59.3
2017-01-01	60.4
2017-04-01	62.2
2017-07-01	64.1
2017-10-01	65.4
2018-01-01	64.0
2018-04-01	64.5