Year Percent 2005-01-01 29.1082760173550 2006-01-01 28.2289673491267 2007-01-01 27.9753146973807 2008-01-01 27.9120888573673 2009-01-01 27.3981978892108 2010-01-01 27.6591383823821 2011-01-01 27.2171521795940 2012-01-01 26.3863738057476 2013-01-01 26.2706845950501 2014-01-01 26.8943970177137 2015-01-01 26.4657482862349 2016-01-01 26.3179481491667 2017-01-01 26.4983792895669