Quarter	Percent
2000-04-01	18.3
2001-04-01	17.3
2002-04-01	17.9
2003-04-01	18.1
2004-04-01	18.6
2005-01-01	19.1
2005-04-01	18.5
2005-07-01	18.5
2005-10-01	18.3
2006-01-01	18.2
2006-04-01	17.1
2006-07-01	17.2
2006-10-01	16.7
2007-01-01	16.3
2007-04-01	15.4
2007-07-01	15.5
2007-10-01	14.9
2008-01-01	15
2008-04-01	15.2
2008-07-01	15.8
2008-10-01	16.5
2009-01-01	19
2009-04-01	19.7
2009-07-01	20.5
2009-10-01	20.5
2010-01-01	21.7
2010-04-01	21.0
2010-07-01	20.7
2010-10-01	20.9
2011-01-01	21.8
2011-04-01	21.2
2011-07-01	21.6
2011-10-01	22.2
2012-01-01	23.3
2012-04-01	22.8
2012-07-01	23.0
2012-10-01	23.7
2013-01-01	24.5
2013-04-01	23.5
2013-07-01	23.3
2013-10-01	23.3
2014-01-01	23.7
2014-04-01	22.0
2014-07-01	21.6
2014-10-01	21.5
2015-01-01	21.5
2015-04-01	20.4
2015-07-01	19.9
2015-10-01	19.6
2016-01-01	19.5
2016-04-01	18.7
2016-07-01	18.5
2016-10-01	18.1
2017-01-01	17.7
2017-04-01	16.9
2017-07-01	16.6
2017-10-01	16.2
2018-01-01	15.8
2018-04-01	15.0