Quarter	Percent
1998-01-01	48.3
1998-04-01	47.8
1998-07-01	48.1
1998-10-01	49.7
1999-01-01	48.0
1999-04-01	47.1
1999-07-01	48.0
1999-10-01	48.7
2000-01-01	47.2
2000-04-01	46.8
2000-07-01	47.6
2000-10-01	48.4
2001-01-01	48.2
2001-04-01	48
2001-07-01	48.4
2001-10-01	47.8
2002-01-01	46
2002-04-01	46.2
2002-07-01	46.3
2002-10-01	47.7
2003-01-01	46.2
2003-04-01	45.9
2003-07-01	46.1
2003-10-01	46
2004-01-01	47.2
2004-04-01	46.8
2004-07-01	47.1
2004-10-01	46.2
2005-01-01	46.3
2005-04-01	46
2005-07-01	46.5
2005-10-01	46.5
2006-01-01	47
2006-04-01	46.6
2006-07-01	46.2
2006-10-01	46.5
2007-01-01	45.8
2007-04-01	45.8
2007-07-01	44.8
2007-10-01	45.1
2008-01-01	45.9
2008-04-01	45.1
2008-07-01	45.5
2008-10-01	46.4
2009-01-01	45.9
2009-04-01	46.3
2009-07-01	46.2
2009-10-01	46.4
2010-01-01	45.9
2010-04-01	45.7
2010-07-01	45.8
2010-10-01	45.4
2011-01-01	45.6
2011-04-01	46
2011-07-01	46.3
2011-10-01	47.7
2012-01-01	46.8
2012-04-01	46.4
2012-07-01	46.4
2012-10-01	47.1
2013-01-01	46.9
2013-04-01	45.1
2013-07-01	45.6
2013-10-01	45
2014-01-01	44.9
2014-04-01	44.8
2014-07-01	44.7
2014-10-01	44.5
2015-01-01	43.5
2015-04-01	42.7
2015-07-01	42.9
2015-10-01	42.9
2016-01-01	43.3
2016-04-01	41.2
2016-07-01	40.9
2016-10-01	40.7
2017-01-01	40.1
2017-04-01	38.9
2017-07-01	37.8
2017-10-01	37.3
2018-01-01	36.9
2018-04-01	36.5