Quarter	Percent
2000-04-01	16.6
2001-04-01	15.0
2002-04-01	15.6
2003-04-01	16.6
2004-04-01	17.4
2005-01-01	18.2
2005-04-01	17.2
2005-07-01	16.7
2005-10-01	16.7
2006-01-01	17.1
2006-04-01	15.5
2006-07-01	15
2006-10-01	15.4
2007-01-01	14.8
2007-04-01	14
2007-07-01	14
2007-10-01	14.2
2008-01-01	14.5
2008-04-01	14.6
2008-07-01	15.1
2008-10-01	17.0
2009-01-01	20.3
2009-04-01	21.1
2009-07-01	20.7
2009-10-01	21.7
2010-01-01	23.1
2010-04-01	21.8
2010-07-01	20.6
2010-10-01	20.7
2011-01-01	21.9
2011-04-01	21.3
2011-07-01	20.8
2011-10-01	22.2
2012-01-01	23.7
2012-04-01	23.8
2012-07-01	23.3
2012-10-01	24.8
2013-01-01	26.1
2013-04-01	24.5
2013-07-01	23.8
2013-10-01	24.3
2014-01-01	25.5
2014-04-01	24.4
2014-07-01	23.2
2014-10-01	23.7
2015-01-01	24.0
2015-04-01	23.1
2015-07-01	22.0
2015-10-01	22.8
2016-01-01	22.7
2016-04-01	21.6
2016-07-01	20.3
2016-10-01	21.0
2017-01-01	20.7
2017-04-01	19.7
2017-07-01	18.7
2017-10-01	18.5
2018-01-01	18.4
2018-04-01	17.6