Quarter	Percent
1999-01-01	30.5
1999-04-01	31
1999-07-01	30.3
1999-10-01	30.3
2000-01-01	30.1
2000-04-01	30.5
2000-07-01	30
2000-10-01	29.9
2001-01-01	29.7
2001-04-01	29.6
2001-07-01	29.3
2001-10-01	29.6
2002-01-01	30.2
2002-04-01	30.5
2002-07-01	30
2002-10-01	29.9
2003-01-01	30.2
2003-04-01	30.2
2003-07-01	29.7
2003-10-01	29.9
2004-01-01	30.3
2004-04-01	30.3
2004-07-01	30.1
2004-10-01	30.5
2005-01-01	30.9
2005-04-01	31.4
2005-07-01	31.1
2005-10-01	30.8
2006-01-01	31.4
2006-04-01	31.4
2006-07-01	31.2
2006-10-01	31.4
2007-01-01	32
2007-04-01	32
2007-07-01	31.5
2007-10-01	31.3
2008-01-01	31.5
2008-04-01	31.4
2008-07-01	30.7
2008-10-01	31.1
2009-01-01	31.9
2009-04-01	31.9
2009-07-01	31.2
2009-10-01	31.3
2010-01-01	31.6
2010-04-01	31.5
2010-07-01	31.1
2010-10-01	31.1
2011-01-01	31.6
2011-04-01	31.5
2011-07-01	31.2
2011-10-01	30.9
2012-01-01	30.6
2012-04-01	30.7
2012-07-01	30.4
2012-10-01	30.6
2013-01-01	30
2013-04-01	30.3
2013-07-01	30.1
2013-10-01	30.2
2014-01-01	29.9
2014-04-01	30
2014-07-01	29.6
2014-10-01	29.4
2015-01-01	29.2
2015-04-01	29.5
2015-07-01	28.9
2015-10-01	28.7
2016-01-01	28.4
2016-04-01	28.1
2016-07-01	28.0
2016-10-01	28.0
2017-01-01	27.9
2017-04-01	28.0
2017-07-01	27.8
2017-10-01	27.9
2018-01-01	27.8
2018-04-01	28.0