Year Percent 2005-01-01 31.37330258775340 2006-01-01 34.69527059970720 2007-01-01 22.84442192137820 2008-01-01 18.38406459027020 2009-01-01 4.68438868976490 2010-01-01 15.46198107375540 2011-01-01 21.35046642367330 2012-01-01 15.22510139320200 2013-01-01 11.88789561273030 2014-01-01 9.71397733405286 2015-01-01 8.15087077489716 2016-01-01 8.17268112275134 2017-01-01 8.91513169824086