Quarter	Percent
1999-04-01	73.5
2000-04-01	72.4
2001-04-01	75.1
2002-04-01	72.1
2003-01-01	69.3
2003-04-01	69.3
2003-07-01	69.3
2003-10-01	69.3
2004-01-01	69.1
2004-04-01	69.1
2004-07-01	69.1
2004-10-01	69.1
2005-01-01	67.6
2005-04-01	67.6
2005-07-01	67.6
2005-10-01	67.6
2006-01-01	66.4
2006-04-01	66.4
2006-07-01	66.4
2006-10-01	66.4
2007-01-01	69
2007-04-01	66.5
2007-07-01	64.6
2007-10-01	69.2
2008-01-01	67.5
2008-04-01	61.4
2008-07-01	62.7
2008-10-01	68.2
2009-01-01	61.4
2009-04-01	56.7
2009-07-01	61.8
2009-10-01	62.6
2010-01-01	60.9
2010-04-01	56.7
2010-07-01	61
2010-10-01	59.2
2011-01-01	59.1
2011-04-01	61
2011-07-01	56.7
2011-10-01	61.6
2012-01-01	57.3
2012-04-01	59.6
2012-07-01	57
2012-10-01	58.6
2013-01-01	58.3
2013-04-01	53.5
2013-07-01	58.5
2013-10-01	59.9
2014-01-01	56.7
2014-04-01	54.9
2014-07-01	55.6
2014-10-01	55.1
2015-01-01	56.0
2015-04-01	58.0
2015-07-01	64.0
2015-10-01	60.7
2016-01-01	57.1
2016-04-01	58.3
2016-07-01	60.1
2016-10-01	57.9
2017-01-01	57.8
2017-04-01	59.0
2017-07-01	59.6
2017-10-01	59.3
2018-01-01	59.0
2018-04-01	59.0