Year Percent 2004-12-31 4.86 2005-12-31 4.54 2006-12-31 5.38 2007-12-31 5.93 2008-12-31 3.1 2009-12-31 0.6 2010-12-31 1.04 2011-12-31 1.28 2012-12-31 0.67