Year Percent 1998-01-01 57.6505325170056 1999-01-01 57.6259007501792 2000-01-01 51.7736542466122 2001-01-01 49.3590379792871 2002-01-01 48.7360912841857 2003-01-01 48.5335526544980 2004-01-01 48.4541037011954 2005-01-01 48.8036443744609 2006-01-01 49.5472551651425 2007-01-01 50.1933059265553 2008-01-01 50.9317216657016 2009-01-01 48.3009401785861 2010-01-01 48.1909959881943 2011-01-01 48.6940382725086 2012-01-01 48.3963162087578 2013-01-01 47.5347473971820