Quarter	Percent
1998-01-01	60.2
1998-04-01	60.5
1998-07-01	60.5
1998-10-01	61.6
1999-01-01	58.7
1999-04-01	57.7
1999-07-01	58.9
1999-10-01	58.9
2000-01-01	57.5
2000-04-01	56.9
2000-07-01	58.6
2000-10-01	59.5
2001-01-01	59.0
2001-04-01	58.3
2001-07-01	58.6
2001-10-01	57.8
2002-01-01	55.8
2002-04-01	56.2
2002-07-01	55.9
2002-10-01	56.7
2003-01-01	55
2003-04-01	56
2003-07-01	56.5
2003-10-01	56.2
2004-01-01	56.8
2004-04-01	55.4
2004-07-01	54.7
2004-10-01	54.3
2005-01-01	54.3
2005-04-01	53.4
2005-07-01	54
2005-10-01	54.3
2006-01-01	55.1
2006-04-01	54.5
2006-07-01	54.7
2006-10-01	55.1
2007-01-01	54
2007-04-01	53.3
2007-07-01	52
2007-10-01	52.7
2008-01-01	53.5
2008-04-01	52.5
2008-07-01	53.1
2008-10-01	54.2
2009-01-01	53.6
2009-04-01	54.2
2009-07-01	54.1
2009-10-01	54.2
2010-01-01	52.9
2010-04-01	52.7
2010-07-01	52.6
2010-10-01	52.1
2011-01-01	53.2
2011-04-01	53
2011-07-01	53.3
2011-10-01	54.7
2012-01-01	53.5
2012-04-01	52.9
2012-07-01	52.2
2012-10-01	53.6
2013-01-01	54
2013-04-01	52.6
2013-07-01	53.3
2013-10-01	52.7
2014-01-01	53.3
2014-04-01	53
2014-07-01	51.8
2014-10-01	52
2015-01-01	50.4
2015-04-01	49.9
2015-07-01	49.6
2015-10-01	50.4
2016-01-01	50.3
2016-04-01	49.1
2016-07-01	49.0
2016-10-01	47.8
2017-01-01	47.3
2017-04-01	45.3
2017-07-01	44.4
2017-10-01	44.5
2018-01-01	42.3
2018-04-01	41.6