Year Percent 2006-01-01 2.86781867449818 2007-01-01 2.93088461814250 2008-01-01 3.26827669993484 2009-01-01 4.32907770189254 2010-01-01 3.77964455124572 2011-01-01 3.21267647307034 2012-01-01 2.99213773689198 2013-01-01 3.27943719253511 2014-01-01 3.75527967904496