Year Percent 2002-01-01 3.20 2003-01-01 3.01 2004-01-01 2.12 2005-01-01 2.65 2006-01-01 2.73 2007-01-01 3.00 2008-01-01 3.09 2009-01-01 3.44 2010-01-01 3.82 2011-01-01 3.69 2012-01-01 3.92 2013-01-01 3.81 2014-01-01 4.30 2015-01-01 4.74 2016-01-01 5.13