Quarter	Percent
1998-04-01	44.1
1998-10-01	45.4
1999-04-01	45.9
1999-10-01	45.7
2000-04-01	46.4
2000-10-01	45.5
2001-04-01	45.0
2001-10-01	45.3
2002-01-01	45.8
2002-04-01	43.3
2002-07-01	44.7
2002-10-01	43.2
2003-01-01	44.7
2003-04-01	43.7
2003-07-01	42.5
2003-10-01	44.2
2004-01-01	42.9
2004-04-01	43.6
2004-07-01	43.1
2004-10-01	42.3
2005-01-01	44.7
2005-04-01	42.9
2005-07-01	43.9
2005-10-01	42.6
2006-01-01	43.1
2006-04-01	40.8
2006-07-01	41.0
2006-10-01	41.4
2007-01-01	42.1
2007-04-01	40.4
2007-07-01	39.8
2007-10-01	39.3
2008-01-01	38.7
2008-04-01	37.4
2008-07-01	38.0
2008-10-01	38.4
2009-01-01	36.8
2009-04-01	37.7
2009-07-01	40.1
2009-10-01	39.1
2010-01-01	39.4
2010-04-01	38.7
2010-07-01	38.1
2010-10-01	39.4
2011-01-01	40.6
2011-04-01	39.0
2011-07-01	39.1
2011-10-01	39.6
2012-01-01	38.6
2012-04-01	37.4
2012-07-01	37.4
2012-10-01	37.8
2013-01-01	38.1
2013-04-01	37.7
2013-07-01	36.9
2013-10-01	38.5
2014-01-01	37.4
2014-04-01	37.4
2014-07-01	37.9
2014-10-01	39.0
2015-01-01	37.8
2015-04-01	36.9
2015-07-01	36.0
2015-10-01	36.3
2016-01-01	35.6
2016-04-01	35.2
2016-07-01	35.7
2016-10-01	35.2
2017-01-01	35.8
2017-04-01	35.1
2017-07-01	34.2
2017-10-01	34.6
2018-01-01	34.4
2018-04-01	33.9