Quarter	Percent
1998-04-01	29.4
1998-10-01	27.8
1999-04-01	28.0
1999-10-01	27.1
2000-04-01	24.9
2000-10-01	22.7
2001-04-01	23.6
2001-10-01	24.8
2002-01-01	24.8
2002-04-01	25.3
2002-07-01	26.2
2002-10-01	24.0
2003-01-01	24.1
2003-04-01	23.7
2003-07-01	26.4
2003-10-01	24.6
2004-01-01	25.0
2004-04-01	21.2
2004-07-01	24.5
2004-10-01	25.0
2005-01-01	23.4
2005-04-01	27.9
2005-07-01	27.8
2005-10-01	25.2
2006-01-01	25.9
2006-04-01	28.6
2006-07-01	31.1
2006-10-01	28.6
2007-01-01	29.8
2007-04-01	33.9
2007-07-01	31.6
2007-10-01	33.7
2008-01-01	35.5
2008-04-01	34.0
2008-07-01	33.0
2008-10-01	24.4
2009-01-01	26.7
2009-04-01	24.8
2009-07-01	26.7
2009-10-01	23.4
2010-01-01	24.3
2010-04-01	24.5
2010-07-01	26.8
2010-10-01	21.4
2011-01-01	21.4
2011-04-01	22.2
2011-07-01	24.3
2011-10-01	25.5
2012-01-01	25.0
2012-04-01	25.0
2012-07-01	23.3
2012-10-01	28.5
2013-01-01	25.5
2013-04-01	26.8
2013-07-01	27.6
2013-10-01	28.2
2014-01-01	27.9
2014-04-01	28.0
2014-07-01	27.9
2014-10-01	29.3
2015-01-01	31.7
2015-04-01	32.2
2015-07-01	29.7
2015-10-01	34.0
2016-01-01	32.9
2016-04-01	32.4
2016-07-01	29.5
2016-10-01	31.4
2017-01-01	28.5
2017-04-01	34.5
2017-07-01	31.7
2017-10-01	28.9
2018-01-01	31.1
2018-04-01	33.5