Year Ratio 1970-01-01 0.508740007877350 1971-01-01 1.215360045433040 1972-01-01 0.577660024166107 1973-01-01 0.666939973831177 1974-01-01 0.398350000381470 1975-01-01 0.408800005912781 1985-01-01 0.610360026359558 1986-01-01 0.535650014877319 2003-01-01 1.198439955711360 2004-01-01 1.196149945259090 2005-01-01 1.193760037422180