Quarter	Percent
1999-04-01	51.2
1999-07-01	53.8
1999-10-01	52.6
2000-01-01	52.6
2000-04-01	53.2
2000-07-01	55.6
2000-10-01	54.2
2001-01-01	54
2001-04-01	54
2001-07-01	56.5
2001-10-01	55.1
2002-01-01	55.1
2002-04-01	55.2
2002-07-01	56.4
2002-10-01	54.9
2003-01-01	55
2003-04-01	55.3
2003-07-01	56.6
2003-10-01	55.9
2004-01-01	55.8
2004-04-01	55.8
2004-07-01	57.3
2004-10-01	57.2
2005-01-01	57.5
2005-04-01	58
2005-07-01	59.3
2005-10-01	58.4
2006-01-01	58.6
2006-04-01	58.7
2006-07-01	60.1
2006-10-01	59.6
2007-01-01	62.2
2007-04-01	62.8
2007-07-01	63.7
2007-10-01	62.9
2008-01-01	62.7
2008-04-01	62.5
2008-07-01	62.4
2008-10-01	61.2
2009-01-01	59.7
2009-04-01	59.3
2009-07-01	59.0
2009-10-01	58.3
2010-01-01	57.3
2010-04-01	57.4
2010-07-01	57.0
2010-10-01	56.6
2011-01-01	56.1
2011-04-01	56.8
2011-07-01	56.0
2011-10-01	56.3
2012-01-01	55.8
2012-04-01	56.3
2012-07-01	56.2
2012-10-01	56.5
2013-01-01	56.1
2013-04-01	57.1
2013-07-01	57.7
2013-10-01	57.6
2014-01-01	57.1
2014-04-01	57.5
2014-07-01	58.4
2014-10-01	59.0
2015-01-01	58.3
2015-04-01	59.0
2015-07-01	59.6
2015-10-01	60.5
2016-01-01	60.1
2016-04-01	61.3
2016-07-01	61.6
2016-10-01	61.7
2017-01-01	61.6
2017-04-01	62.3
2017-07-01	62.4
2017-10-01	63.1
2018-01-01	62.3
2018-04-01	63.4