Year Percent 2000-01-01 8.32 2001-01-01 8.99 2002-01-01 12.55 2003-01-01 16.90 2004-01-01 19.62 2005-01-01 18.24 2006-01-01 20.90 2007-01-01 20.90 2008-01-01 16.54 2009-01-01 21.03 2010-01-01 17.62 2011-01-01 16.05 2012-01-01 18.20 2013-01-01 15.73 2014-01-01 14.74