Year Ratio 1970-01-01 0.826089978218079 1971-01-01 0.825089991092682 1972-01-01 0.827820003032684 1973-01-01 0.827610015869141 1974-01-01 0.840020000934601 1975-01-01 0.841239988803864 1976-01-01 0.846830010414124 1977-01-01 0.846549987792969 1978-01-01 0.851249992847443 1979-01-01 0.846340000629425 1980-01-01 0.847050011157990 1981-01-01 0.850629985332489 1982-01-01 0.870630025863647 1983-01-01 0.854600012302399 1985-01-01 0.847069978713989 1986-01-01 0.849009990692139 1991-01-01 0.869180023670197 1992-01-01 0.868130028247833 1993-01-01 0.869310021400452 1994-01-01 0.863520026206970 1995-01-01 0.866419970989227 1996-01-01 0.865949988365173 1997-01-01 0.870310008525848 1998-01-01 0.877009987831116 1999-01-01 0.878300011157990 2000-01-01 0.904219985008240 2001-01-01 0.911360025405884 2002-01-01 0.920830011367798 2004-01-01 0.932060003280640 2005-01-01 0.938289999961853 2006-01-01 0.945100009441376 2007-01-01 0.953079998493195 2008-01-01 0.958880007266998 2009-01-01 0.971459984779358 2010-01-01 0.979719996452332 2011-01-01 0.984019994735718 2012-01-01 0.978349983692169 2013-01-01 0.972509980201721 2014-01-01 0.970589995384216 2015-01-01 0.968940019607544 2016-01-01 0.967790007591248