Year Percent 1999-01-01 53.3856139152783 2000-01-01 53.0601591089936 2001-01-01 53.3394612670151 2002-01-01 54.0509473155555 2003-01-01 53.7120871102685 2004-01-01 53.3805000421661 2005-01-01 54.2461476123421 2006-01-01 54.7024431757382 2007-01-01 55.6157679277411 2008-01-01 56.0606980285014 2009-01-01 54.7671561314972 2010-01-01 54.1709785798000 2011-01-01 53.9002748253351 2012-01-01 53.8117808346652 2013-01-01 54.0743671825031