Year Percent 2005-01-01 3.67789121949387 2006-01-01 3.68119410773974 2007-01-01 3.76568690879688 2008-01-01 4.03011729708269 2009-01-01 5.55800496456374 2010-01-01 5.50637244278384 2011-01-01 5.36612734059543 2012-01-01 5.08445234310507 2013-01-01 5.10486092310992 2014-01-01 5.00280555050138 2015-01-01 4.50195545050082 2016-01-01 4.03632441015680 2017-01-01 3.56810674255278