Quarter	Percent
1999-01-01	54.8
1999-04-01	55.4
1999-07-01	55.9
1999-10-01	56.1
2000-01-01	55.5
2000-04-01	55.9
2000-07-01	56.6
2000-10-01	56.9
2001-01-01	56
2001-04-01	56.1
2001-07-01	56.5
2001-10-01	56.2
2002-01-01	55.8
2002-04-01	56.2
2002-07-01	56.4
2002-10-01	56.5
2003-01-01	56.1
2003-04-01	57
2003-07-01	57.5
2003-10-01	57.5
2004-01-01	56.6
2004-04-01	56.6
2004-07-01	56.8
2004-10-01	57
2005-01-01	56.4
2005-04-01	56.8
2005-07-01	57.3
2005-10-01	57.1
2006-01-01	56.8
2006-04-01	57.5
2006-07-01	57.5
2006-10-01	57.6
2007-01-01	56.8
2007-04-01	57.2
2007-07-01	57.4
2007-10-01	56.7
2008-01-01	55.9
2008-04-01	56.3
2008-07-01	57
2008-10-01	56.4
2009-01-01	54.8
2009-04-01	55.3
2009-07-01	55.1
2009-10-01	55
2010-01-01	54.1
2010-04-01	54.9
2010-07-01	55.5
2010-10-01	55.3
2011-01-01	54.3
2011-04-01	55.4
2011-07-01	56
2011-10-01	56
2012-01-01	55.2
2012-04-01	56.5
2012-07-01	57.6
2012-10-01	57.4
2013-01-01	56.1
2013-04-01	57.9
2013-07-01	58.9
2013-10-01	59.4
2014-01-01	60.6
2014-04-01	61.3
2014-07-01	62.6
2014-10-01	62.6
2015-01-01	62.4
2015-04-01	63.8
2015-07-01	64.8
2015-10-01	64.8
2016-01-01	65.1
2016-04-01	66.4
2016-07-01	67.1
2016-10-01	67.5
2017-01-01	67.1
2017-04-01	68.1
2017-07-01	68.7
2017-10-01	68.8
2018-01-01	68.7
2018-04-01	69.3