Quarter	Percent
1998-04-01	53.5
1998-10-01	53.6
1999-04-01	52.8
1999-10-01	52.5
2000-04-01	51.4
2000-10-01	51.4
2001-04-01	52.1
2001-10-01	52.3
2002-01-01	52.0
2002-04-01	53.6
2002-07-01	55.1
2002-10-01	54.7
2003-01-01	53.9
2003-04-01	54.1
2003-07-01	55.7
2003-10-01	54.3
2004-01-01	54.4
2004-04-01	54.7
2004-07-01	55.4
2004-10-01	55.1
2005-01-01	54.3
2005-04-01	55.8
2005-07-01	56.4
2005-10-01	57.0
2006-01-01	57.7
2006-04-01	59.2
2006-07-01	61.6
2006-10-01	60.1
2007-01-01	59.4
2007-04-01	61.2
2007-07-01	63.0
2007-10-01	63.0
2008-01-01	62.3
2008-04-01	63.1
2008-07-01	62.4
2008-10-01	60.1
2009-01-01	57.8
2009-04-01	55.2
2009-07-01	52.5
2009-10-01	51.5
2010-01-01	50.8
2010-04-01	51.5
2010-07-01	53.1
2010-10-01	52.7
2011-01-01	52.4
2011-04-01	53.8
2011-07-01	54.9
2011-10-01	55.0
2012-01-01	54.4
2012-04-01	55.6
2012-07-01	57.4
2012-10-01	57.2
2013-01-01	57.3
2013-04-01	57.9
2013-07-01	59.0
2013-10-01	58.6
2014-01-01	58.6
2014-04-01	59.3
2014-07-01	59.3
2014-10-01	59.3
2015-01-01	59.7
2015-04-01	60.9
2015-07-01	61.4
2015-10-01	61.4
2016-01-01	61.0
2016-04-01	61.8
2016-07-01	61.8
2016-10-01	61.7
2017-01-01	61.6
2017-04-01	62.6
2017-07-01	63.6
2017-10-01	63.7
2018-01-01	63.5
2018-04-01	64.4