Year Ratio 1971-01-01 0.161620005965233 1972-01-01 0.149770006537437 1973-01-01 0.204929992556572 1974-01-01 0.291779994964600 1975-01-01 0.345899999141693 1976-01-01 0.387459993362427 1977-01-01 0.413580000400543 1978-01-01 0.446060001850128 1979-01-01 0.484910011291504 1980-01-01 0.498670011758804 1981-01-01 0.536880016326904 1982-01-01 0.572149991989136 1983-01-01 0.630349993705750 1984-01-01 0.693809986114502 1985-01-01 0.760770022869110 1986-01-01 0.817390024662018 1987-01-01 0.846109986305237 1988-01-01 0.868550002574921 1989-01-01 0.882809996604919 1990-01-01 0.898810029029846 1991-01-01 0.922399997711182 1992-01-01 0.930339992046356 1993-01-01 0.954200029373169 1994-01-01 0.980929970741272 1995-01-01 0.989229977130890 1996-01-01 0.969449996948242 1997-01-01 0.983539998531342 1998-01-01 0.983730018138886 1999-01-01 0.975489974021912 2000-01-01 0.969739973545074 2001-01-01 0.979309976100922 2002-01-01 0.967599987983704 2003-01-01 0.965439975261688 2005-01-01 0.987339973449707 2006-01-01 1.004879951477050 2007-01-01 0.993430018424988 2008-01-01 0.987640023231506 2009-01-01 0.960780024528503 2011-01-01 1.012840032577510 2012-01-01 1.006340026855470 2013-01-01 1.056139945983890 2014-01-01 1.056920051574710 2015-01-01 1.040639996528630 2016-01-01 1.027160048484800