Year Percent 2004-01-01 3.37 2005-01-01 4.43 2006-01-01 2.81 2007-01-01 3.29 2008-01-01 2.71 2009-01-01 3.46 2010-01-01 3.16 2011-01-01 1.88 2012-01-01 1.86 2013-01-01 2.29 2014-01-01 4.09 2015-01-01 6.65