Year Percent 2000-01-01 25.7000 2001-01-01 18.6000 2002-01-01 17.2000 2003-01-01 16.9000 2004-01-01 15.3000 2005-01-01 14.9000 2006-01-01 14.8000 2007-01-01 14.2000 2008-01-01 14.9000 2009-01-01 9.5000 2010-01-01 17.3186 2011-01-01 17.5311 2012-01-01 17.4732 2013-01-01 17.8055 2014-01-01 17.8984 2015-01-01 15.9100 2016-01-01 16.3466