Year Percent 1996-01-01 56.2500 1997-01-01 54.5977 1998-01-01 48.5756 1999-01-01 19.9881 2000-01-01 19.9896 2001-01-01 24.7599 2002-01-01 23.5411 2003-01-01 21.4286 2004-01-01 19.9881 2005-01-01 59.6587 2006-01-01 36.7078 2007-01-01 36.6009 2008-01-01 36.6009 2009-01-01 19.9881 2010-01-01 26.7691 2011-01-01 44.6600 2012-01-01 55.5375 2013-01-01 63.4101 2014-01-01 60.9972