Quarter	Percent
1998-04-01	66.1
1999-01-01	64.9
1999-04-01	63.2
1999-07-01	65.1
1999-10-01	65.4
2000-01-01	62.3
2000-04-01	63.7
2000-07-01	61.4
2000-10-01	62.6
2001-01-01	64.5
2001-04-01	63.4
2001-07-01	63.8
2001-10-01	63
2002-01-01	62.2
2002-04-01	63.7
2002-07-01	61.5
2002-10-01	62.8
2003-01-01	64.8
2003-04-01	60.6
2003-07-01	60.5
2003-10-01	58.6
2004-01-01	60.3
2004-04-01	59
2004-07-01	59.1
2004-10-01	60.2
2005-01-01	57.6
2005-04-01	56.8
2005-07-01	54.6
2005-10-01	57.4
2006-01-01	57.8
2006-04-01	59.9
2006-07-01	57.5
2006-10-01	54
2007-01-01	53.7
2007-04-01	57.8
2007-07-01	55.3
2007-10-01	55.3
2008-01-01	55.6
2008-04-01	57.2
2008-07-01	55
2008-10-01	54.4
2009-01-01	55.3
2009-04-01	56.1
2009-07-01	54.4
2009-10-01	53.6
2010-01-01	54.2
2010-04-01	51.9
2010-07-01	52.5
2010-10-01	51.1
2011-01-01	53.5
2011-04-01	51.5
2011-07-01	52.3
2011-10-01	51.4
2012-01-01	52.4
2012-04-01	52
2012-07-01	51.6
2012-10-01	52.4
2013-01-01	50.4
2013-04-01	48.6
2013-07-01	48.9
2013-10-01	50.1
2014-01-01	49.5
2014-04-01	47.9
2014-07-01	50.6
2014-10-01	46.9
2015-01-01	48.4
2015-04-01	48.1
2015-07-01	46.7
2015-10-01	48.1
2016-01-01	48.5
2016-04-01	45.0
2016-07-01	45.9
2016-10-01	46.2
2017-01-01	44.5
2017-04-01	44.2
2017-07-01	43.6
2017-10-01	40.2
2018-01-01	41.5
2018-04-01	42.5