Year Ratio 1993-01-01 0.982150018215179 1994-01-01 0.985339999198914 1995-01-01 0.985509991645813 1996-01-01 0.983060002326965 1997-01-01 0.984080016613007 1998-01-01 0.976949989795685 1999-01-01 0.975600004196167 2000-01-01 0.967599987983704 2001-01-01 0.968540012836456 2002-01-01 0.970879971981049 2003-01-01 0.973089993000031 2004-01-01 0.969910025596619 2005-01-01 0.968840003013611 2007-01-01 0.960749983787537 2008-01-01 0.950810015201569 2009-01-01 0.959079980850220 2010-01-01 0.971629977226257 2012-01-01 0.980579972267151 2013-01-01 0.972019970417023 2014-01-01 0.970239996910095 2015-01-01 0.983389973640442