Year Percent 2005-01-01 4.07 2006-01-01 6.11 2007-01-01 8.32 2008-01-01 3.99 2009-01-01 5.13 2010-01-01 5.65 2011-01-01 4.91 2012-01-01 5.07 2013-01-01 5.12 2014-01-01 5.72 2015-01-01 5.97 2016-01-01 6.12