Year Percent 2000-01-01 57.7080882385712 2001-01-01 58.1476850000000 2002-01-01 57.9198950000000 2003-01-01 56.9214525000000 2004-01-01 56.3362775000000 2005-01-01 56.0946825000000 2006-01-01 56.8594450000000 2007-01-01 57.7286650000000 2008-01-01 58.2538100000000 2009-01-01 57.7978050000000 2010-01-01 55.8532325000000 2011-01-01 55.3583350000000 2012-01-01 55.2648825000000 2013-01-01 54.3467325000000