Quarter	Percent
1999-04-01	37.1
2000-04-01	37
2001-04-01	36.3
2002-04-01	35.8
2003-04-01	35
2004-04-01	34.9
2005-01-01	33.3
2005-04-01	33.3
2005-07-01	33
2005-10-01	32.7
2006-01-01	31.9
2006-04-01	31.8
2006-07-01	31.3
2006-10-01	31
2007-01-01	31
2007-04-01	31
2007-07-01	30.4
2007-10-01	30.2
2008-01-01	30.6
2008-04-01	30.6
2008-07-01	30.1
2008-10-01	29.9
2009-01-01	30.2
2009-04-01	29.7
2009-07-01	29.7
2009-10-01	28.9
2010-01-01	29.3
2010-04-01	29.3
2010-07-01	29.1
2010-10-01	28.7
2011-01-01	28.7
2011-04-01	28.2
2011-07-01	27.8
2011-10-01	27.7
2012-01-01	28.7
2012-04-01	28.2
2012-07-01	28
2012-10-01	27.7
2013-01-01	27.6
2013-04-01	27.5
2013-07-01	27.2
2013-10-01	27.2
2014-01-01	27.4
2014-04-01	27.2
2014-07-01	26.9
2014-10-01	27
2015-01-01	27.0
2015-04-01	27.0
2015-07-01	27.1
2015-10-01	26.7
2016-01-01	26.7
2016-04-01	26.9
2016-07-01	26.0
2016-10-01	25.9
2017-01-01	26.3
2017-04-01	26.6
2017-07-01	25.8
2017-10-01	25.4
2018-01-01	26.0
2018-04-01	26.2