Quarter	Percent
1998-01-01	37.5
1998-04-01	37.7
1998-07-01	38.0
1998-10-01	37.5
1999-01-01	37.2
1999-04-01	37.0
1999-07-01	37.0
1999-10-01	36.9
2000-01-01	36.2
2000-04-01	36.3
2000-07-01	35.8
2000-10-01	36
2001-01-01	35.2
2001-04-01	35.4
2001-07-01	35.4
2001-10-01	35
2002-01-01	35
2002-04-01	34.6
2002-07-01	34.2
2002-10-01	34
2003-01-01	33.4
2003-04-01	33.5
2003-07-01	33.8
2003-10-01	33.7
2004-01-01	33.8
2004-04-01	33.5
2004-07-01	33
2004-10-01	32.6
2005-01-01	32.6
2005-04-01	32.4
2005-07-01	32
2005-10-01	31.9
2006-01-01	32
2006-04-01	31.8
2006-07-01	31.5
2006-10-01	31.6
2007-01-01	31.5
2007-04-01	31.5
2007-07-01	31
2007-10-01	31
2008-01-01	31.4
2008-04-01	30.8
2008-07-01	30.9
2008-10-01	31.4
2009-01-01	31
2009-04-01	31.3
2009-07-01	31.3
2009-10-01	31
2010-01-01	30.3
2010-04-01	30.2
2010-07-01	30.2
2010-10-01	30.5
2011-01-01	30.4
2011-04-01	30
2011-07-01	30.7
2011-10-01	30.9
2012-01-01	30.4
2012-04-01	30.2
2012-07-01	30
2012-10-01	30.5
2013-01-01	30.7
2013-04-01	30.4
2013-07-01	30.2
2013-10-01	29.6
2014-01-01	30.2
2014-04-01	30
2014-07-01	29.7
2014-10-01	30.1
2015-01-01	29.6
2015-04-01	29.6
2015-07-01	29.6
2015-10-01	29.8
2016-01-01	29.6
2016-04-01	29.9
2016-07-01	29.3
2016-10-01	29.2
2017-01-01	28.9
2017-04-01	28.6
2017-07-01	27.9
2017-10-01	28.0
2018-01-01	27.9
2018-04-01	27.6