Year Percent 1998-01-01 11.20000 1999-01-01 11.20000 2000-01-01 10.60000 2001-01-01 10.60000 2002-01-01 10.60000 2003-01-01 10.60000 2004-01-01 10.60000 2005-01-01 10.60000 2006-01-01 4.00000 2007-01-01 3.10000 2008-01-01 4.30000 2009-01-01 4.70000 2010-01-01 3.66355 2011-01-01 2.93742 2012-01-01 3.28720 2013-01-01 3.39336 2014-01-01 3.27080 2015-01-01 3.05632 2016-01-01 2.92120