Year Percent 1996-01-01 57.633700000000000 1997-01-01 61.762300000000000 1998-01-01 58.853900000000000 1999-01-01 55.086200000000000 2000-01-01 53.732000000000000 2001-01-01 54.746300000000000 2002-01-01 51.594900000000000 2003-01-01 54.205000000000000 2004-01-01 50.143900000000000 2005-01-01 56.196700000000000 2006-01-01 52.608000000000004 2007-01-01 55.535600000000000 2008-01-01 49.961300000000000 2009-01-01 31.302600000000000 2010-01-01 45.610100000000000 2011-01-01 27.870300000000000 2012-01-01 20.947500000000000 2013-01-01 22.782100000000000 2014-01-01 23.286200000000000