Quarter	Percent
1999-04-01	57.3
2000-04-01	57.5
2001-04-01	57.7
2002-04-01	57.2
2003-04-01	56.5
2004-04-01	55.7
2005-01-01	56.4
2005-04-01	56.7
2005-07-01	57
2005-10-01	57.2
2006-01-01	57.1
2006-04-01	57.9
2006-07-01	58.4
2006-10-01	58.8
2007-01-01	58.3
2007-04-01	59.1
2007-07-01	59.8
2007-10-01	60
2008-01-01	59.5
2008-04-01	59.6
2008-07-01	60.9
2008-10-01	60.9
2009-01-01	59.8
2009-04-01	60
2009-07-01	60.3
2009-10-01	61.3
2010-01-01	60.4
2010-04-01	61
2010-07-01	61.6
2010-10-01	61.9
2011-01-01	61.9
2011-04-01	62.9
2011-07-01	63.4
2011-10-01	63.7
2012-01-01	62.7
2012-04-01	63.3
2012-07-01	64
2012-10-01	64
2013-01-01	63.5
2013-04-01	64.2
2013-07-01	64.6
2013-10-01	64.6
2014-01-01	64.1
2014-04-01	64.6
2014-07-01	65.2
2014-10-01	65.1
2015-01-01	64.7
2015-04-01	64.8
2015-07-01	65.3
2015-10-01	65.6
2016-01-01	65.6
2016-04-01	65.7
2016-07-01	66.7
2016-10-01	66.9
2017-01-01	66.1
2017-04-01	66.5
2017-07-01	67.2
2017-10-01	67.5
2018-01-01	66.8
2018-04-01	66.9