Year Percent 1996-01-01 44.0252 1997-01-01 48.1189 1998-01-01 28.7274 1999-01-01 35.1089 2000-01-01 40.3568 2001-01-01 26.7252 2002-01-01 18.7004 2003-01-01 12.5000 2004-01-01 23.6032 2005-01-01 27.6909 2006-01-01 12.9722 2007-01-01 16.8721 2008-01-01 17.1617 2009-01-01 19.4357 2010-01-01 28.7661 2011-01-01 16.1303 2012-01-01 11.5016 2013-01-01 11.5016 2014-01-01 14.9254 2015-01-01 10.6032