Year Percent 2002-01-01 2.74 2003-01-01 3.37 2004-01-01 2.55 2005-01-01 2.78 2006-01-01 2.86 2007-01-01 4.01 2008-01-01 2.49 2009-01-01 3.85 2010-01-01 3.75 2011-01-01 2.94 2012-01-01 3.61 2013-01-01 3.09 2014-01-01 3.25 2015-01-01 3.44 2016-01-01 3.83