Quarter	Percent
1999-04-01	17.3
2000-04-01	16.2
2001-04-01	16.5
2002-04-01	17.2
2003-01-01	20.3
2003-04-01	16.9
2003-07-01	16.9
2003-10-01	20.6
2004-01-01	21.3
2004-04-01	18.1
2004-07-01	19
2004-10-01	20.8
2005-01-01	20.6
2005-04-01	17.1
2005-07-01	17.8
2005-10-01	19.1
2006-01-01	19.3
2006-04-01	15.6
2006-07-01	16.7
2006-10-01	18.5
2007-01-01	18.3
2007-04-01	15.7
2007-07-01	16.8
2007-10-01	18.5
2008-01-01	19.5
2008-04-01	16.5
2008-07-01	17.4
2008-10-01	19
2009-01-01	21
2009-04-01	18.7
2009-07-01	18.8
2009-10-01	20.1
2010-01-01	20.7
2010-04-01	17.6
2010-07-01	19.8
2010-10-01	20.4
2011-01-01	21.4
2011-04-01	17.7
2011-07-01	19.9
2011-10-01	21.9
2012-01-01	21.6
2012-04-01	17.9
2012-07-01	19.6
2012-10-01	21.4
2013-01-01	21.7
2013-04-01	17.5
2013-07-01	18.1
2013-10-01	20.1
2014-01-01	20.1
2014-04-01	16.1
2014-07-01	16.9
2014-10-01	18.3
2015-01-01	18.5
2015-04-01	15.1
2015-07-01	16.3
2015-10-01	18.1
2016-01-01	17.9
2016-04-01	14.8
2016-07-01	15.2
2016-10-01	16.9
2017-01-01	16.8
2017-04-01	15.4
2017-07-01	17.8
2017-10-01	18.4
2018-01-01	19.0
2018-04-01	17.0