Quarter	Percent
2000-04-01	26.6
2001-04-01	26.5
2002-04-01	26.1
2003-04-01	25.3
2004-04-01	24.8
2005-01-01	24.5
2005-04-01	24.3
2005-07-01	24.6
2005-10-01	24.1
2006-01-01	23.8
2006-04-01	23.6
2006-07-01	23.7
2006-10-01	23.5
2007-01-01	23.7
2007-04-01	23.5
2007-07-01	23.3
2007-10-01	22.9
2008-01-01	23
2008-04-01	22.8
2008-07-01	22.7
2008-10-01	22.4
2009-01-01	22.6
2009-04-01	22.3
2009-07-01	22.4
2009-10-01	22
2010-01-01	22.0
2010-04-01	21.7
2010-07-01	22
2010-10-01	21.6
2011-01-01	21.7
2011-04-01	21.6
2011-07-01	21.8
2011-10-01	21.3
2012-01-01	21.1
2012-04-01	21.0
2012-07-01	21.1
2012-10-01	20.7
2013-01-01	20.8
2013-04-01	20.6
2013-07-01	21.0
2013-10-01	20.7
2014-01-01	20.5
2014-04-01	20.5
2014-07-01	20.7
2014-10-01	20.4
2015-01-01	20.6
2015-04-01	20.4
2015-07-01	20.8
2015-10-01	20.4
2016-01-01	20.6
2016-04-01	20.4
2016-07-01	20.5
2016-10-01	20.3
2017-01-01	20.4
2017-04-01	20.2
2017-07-01	20.3
2017-10-01	20.1
2018-01-01	20.1
2018-04-01	19.8