Month Percent 1997-07-31 20 1997-08-31 17.9 1997-09-30 18.8 1997-10-31 15.4 1997-11-30 17.5 1997-12-31 22.3 1998-01-31 17.3 1998-02-28 19.3 1998-03-31 16.8 1998-04-30 19 1998-05-31 15.8 1998-06-30 13.9 1998-07-31 17.3 1998-08-31 18.4 1998-09-30 16.9 1998-10-31 19.2 1998-11-30 11.6 1998-12-31 9.9 1999-01-31 9.7 1999-02-28 8.2 1999-03-31 8.4 1999-04-30 8.1 1999-05-31 6 1999-06-30 10.4 1999-07-31 4.3 1999-08-31 8.2 1999-09-30 5.3 1999-10-31 6.6 1999-11-30 11.7 1999-12-31 12.2 2000-01-31 9.7 2000-02-29 9 2000-03-31 14.4 2000-04-30 11.1 2000-05-31 15.5 2000-06-30 12.5 2000-07-31 13.9 2000-08-31 18.1 2000-09-30 17.9 2000-10-31 19.1 2000-11-30 19.2 2000-12-31 19.3 2001-01-31 19.5 2001-02-28 18.9 2001-03-31 17.4 2001-04-30 14.7 2001-05-31 13.2 2001-06-30 16.3 2001-07-31 14.9 2001-08-31 11.3 2001-09-30 11.2 2001-10-31 10.7 2001-11-30 7.2 2001-12-31 4.3 2002-01-31 6.4 2002-02-28 4.1 2002-03-31 1.6 2002-04-30 3 2002-05-31 2.9 2002-06-30 2.7 2002-07-31 0.7 2002-08-31 -1.7 2002-09-30 5.9 2002-10-31 5.1 2002-11-30 6.3 2002-12-31 4.4 2003-01-31 2.7 2003-02-28 4.1 2003-03-31 3.9 2003-04-30 7.8 2003-05-31 6.9 2003-06-30 4.4 2003-07-31 7.6 2003-08-31 5.4 2003-09-30 3.1 2003-10-31 5.4 2003-11-30 4.8 2003-12-31 9.6 2004-01-31 13.3 2004-02-29 9.8 2004-03-31 12 2004-04-30 12.7 2004-05-31 12.1 2004-06-30 13.5 2004-07-31 15.4 2004-08-31 19.3 2004-09-30 19 2004-10-31 16.4 2004-11-30 17 2004-12-31 18 2005-01-31 16 2005-02-28 19.1 2005-03-31 17 2005-04-30 14.7 2005-05-31 16.7 2005-06-30 14 2005-07-31 15.1 2005-08-31 12.4 2005-09-30 13.1 2005-10-31 13.7 2005-11-30 9.2 2005-12-31 12.8 2006-01-31 15.2 2006-02-28 16.6 2006-03-31 19.1 2006-04-30 25.4 2006-05-31 24 2006-06-30 30 2006-07-31 26.5 2006-08-31 28.4 2006-09-30 25.3 2006-10-31 23.9 2006-11-30 30.8 2006-12-31 23.2 2007-01-31 25.6 2007-02-28 23.6 2007-03-31 21.4 2007-04-30 17.6 2007-05-31 21.9 2007-06-30 17.4 2007-07-31 19.3 2007-08-31 23.4 2007-09-30 26.6 2007-10-31 25.7 2007-11-30 24.6 2007-12-31 28.1 2008-01-31 26.3 2008-02-29 24.9 2008-03-31 24.5 2008-04-30 29 2008-05-31 22 2008-06-30 29.5 2008-07-31 32.4 2008-08-31 32.8 2008-09-30 34.5 2008-10-31 45.6 2008-11-30 45.5 2008-12-31 51.1 2009-01-31 49.5 2009-02-28 53.8 2009-03-31 55.8 2009-04-30 45.1 2009-05-31 46.9 2009-06-30 35.4 2009-07-31 31.4 2009-08-31 25.9 2009-09-30 22.9 2009-10-31 17.7 2009-11-30 14.4 2009-12-31 7.7 2010-01-31 6.4 2010-02-28 2.4 2010-03-31 0.7 2010-04-30 0.6 2010-05-31 1.1 2010-06-30 3.1 2010-07-31 0.6 2010-08-31 -2.4 2010-09-30 -2.6 2010-10-31 -3.5 2010-11-30 -4.3 2010-12-31 -7.2 2011-01-31 -9.1 2011-02-28 -7.2 2011-03-31 -7.1 2011-04-30 -3.5 2011-05-31 -4.6 2011-06-30 -4.6 2011-07-31 -3.8 2011-08-31 0.2 2011-09-30 -2.7 2011-10-31 -9 2011-11-30 -8.3 2011-12-31 -4.9 2012-01-31 -7.2 2012-02-29 -10 2012-03-31 -12.4 2012-04-30 -13.4 2012-05-31 -13.7 2012-06-30 -17.8 2012-07-31 -17.6 2012-08-31 -18.8 2012-09-30 -17.5 2012-10-31 -14.4 2012-11-30 -12.5 2012-12-31 -8 2013-01-31 -7.1 2013-02-28 -5.3 2013-03-31 -5.5 2013-04-30 -6.8 2013-05-31 -6 2013-06-30 -3.1 2013-07-31 -2.2 2013-08-31 0.1 2013-09-30 0 2013-10-31 -2.5 2013-11-30 -2.4 2013-12-31 -10.9 2014-01-31 -11 2014-02-28 -10.3 2014-03-31 -15.2 2014-04-30 -17.1 2014-05-31 -17 2014-06-30 -15.7 2014-07-31 -15.2 2014-08-31 -17.6 2014-09-30 -18.9 2014-10-31 -18.3 2014-11-30 -20.1 2014-12-31 -15.7 2015-01-31 -15.9 2015-02-28 -16.4 2015-03-31 -9