Year Percent 1996-01-01 13.5452000000000000 1997-01-01 16.6827000000000000 1998-01-01 18.5172000000000000 1999-01-01 15.8894000000000000 2000-01-01 22.8889000000000000 2001-01-01 8.1242399999999990 2002-01-01 6.8509400000000000 2003-01-01 1.0089500000000000 2004-01-01 9.1392200000000000 2005-01-01 16.4790000000000000 2006-01-01 20.7212000000000000 2007-01-01 23.0828000000000000 2008-01-01 24.4649000000000000 2009-01-01 17.0548000000000000 2010-01-01 16.5892000000000000 2011-01-01 16.5556000000000000 2012-01-01 18.1593000000000000 2013-01-01 16.9975000000000000 2014-01-01 10.3456000000000000 2015-01-01 3.1425400000000003 2016-01-01 16.6379000000000000