Year Percent 1996-01-01 53.710900000000000 1997-01-01 51.851100000000000 1998-01-01 54.134800000000000 1999-01-01 54.382400000000000 2000-01-01 54.185500000000000 2001-01-01 55.295400000000000 2002-01-01 59.978600000000000 2003-01-01 64.466400000000000 2004-01-01 63.073500000000000 2005-01-01 57.845600000000000 2006-01-01 54.765300000000000 2007-01-01 53.407700000000000 2008-01-01 48.256600000000000 2009-01-01 49.880800000000000 2010-01-01 48.876999999999995 2011-01-01 52.947100000000000 2012-01-01 52.624900000000000 2013-01-01 49.441100000000000 2014-01-01 50.264300000000000