Year Ratio 1970-01-01 0.641240000724792 1971-01-01 0.621890008449554 1972-01-01 0.613070011138916 1973-01-01 0.638790011405945 1974-01-01 0.701059997081757 1975-01-01 0.602439999580383 1977-01-01 0.689610004425049 1978-01-01 0.848720014095306 1979-01-01 0.895829975605011 1980-01-01 0.840399980545044 1981-01-01 0.939999997615814 1982-01-01 0.972800016403198 1983-01-01 0.972699999809265 1984-01-01 0.916499972343445 1985-01-01 1.013170003890990 1986-01-01 0.993359982967377 1987-01-01 0.986320018768311 1988-01-01 1.001240015029910 1989-01-01 0.866429984569550 1990-01-01 0.997969985008240 1991-01-01 1.123039960861210 1992-01-01 1.114979982376100 1995-01-01 1.236590027809140 1996-01-01 1.196009993553160 1998-01-01 1.074929952621460 1999-01-01 1.209139943122860 2000-01-01 1.252099990844730 2001-01-01 1.178449988365170 2002-01-01 1.159360051155090 2003-01-01 1.185930013656620 2004-01-01 1.188750028610230 2005-01-01 1.146770000457760 2006-01-01 1.191390037536620 2007-01-01 1.177670001983640 2008-01-01 1.103620052337650