Year Percent 2005-01-01 3.90520739729132 2006-01-01 3.87744647425310 2007-01-01 4.01644920917179 2008-01-01 4.06899496374411 2009-01-01 5.36238844825981 2010-01-01 5.20711110738837 2011-01-01 5.15660644734884 2012-01-01 4.91589418863023 2013-01-01 4.98777646340102 2014-01-01 4.87441043515190 2015-01-01 4.47281278467591 2016-01-01 3.94310323823892 2017-01-01 3.62358658624763