Year Percent 1999-01-01 2.05952093658066 2000-01-01 1.85691255792288 2001-01-01 1.92220789391520 2002-01-01 2.24267780962621 2003-01-01 2.45033130476342 2004-01-01 2.51203660114134 2005-01-01 2.73701462680850 2006-01-01 2.44941358369028 2007-01-01 2.25190045590466 2008-01-01 2.04523953473188 2009-01-01 2.84564672657016 2010-01-01 2.60462793534430 2011-01-01 2.30028315406174 2012-01-01 2.49623667103840 2013-01-01 2.81237226773734