Year Percent 2005-01-01 71.0829051506689 2006-01-01 72.0040808702357 2007-01-01 72.3477720194356 2008-01-01 72.5814443921298 2009-01-01 70.0486163050245 2010-01-01 72.0575382028860 2011-01-01 73.5995363321433 2012-01-01 73.6130303963446 2013-01-01 73.7589956172221 2014-01-01 72.7614671474176 2015-01-01 72.9967480380891 2016-01-01 72.3686331405516 2017-01-01 72.4676208663320