Year Percent 1998-01-01 9.60 1999-01-01 11.10 2000-01-01 13.46 2001-01-01 13.06 2002-01-01 6.52 2003-01-01 5.14 2004-01-01 7.63 2005-01-01 9.31 2006-01-01 16.15 2007-01-01 14.04 2008-01-01 18.25 2009-01-01 9.00 2010-01-01 4.60 2011-01-01 4.30 2012-01-01 5.35 2013-01-01 5.25 2014-01-01 4.50 2015-01-01 5.65 2016-01-01 4.85 2017-01-01 4.10