Year Percent 2005-01-01 4.53941316264683 2006-01-01 4.10211434680799 2007-01-01 3.57055698060289 2008-01-01 3.58798061791832 2009-01-01 4.87121169831463 2010-01-01 5.20672492028887 2011-01-01 5.14555059132797 2012-01-01 5.60651790733941