Year Ratio 1971-01-01 0.802980005741119 1972-01-01 0.819369971752167 1973-01-01 0.832019984722137 1974-01-01 0.845579981803894 1975-01-01 0.856440007686615 1976-01-01 0.873780012130737 1977-01-01 0.866869986057281 1978-01-01 0.865800023078918 1979-01-01 0.866580009460449 1980-01-01 0.863259971141815 1981-01-01 0.852410018444061 1982-01-01 0.867479979991913 1983-01-01 0.886089980602264 1984-01-01 0.908640027046204 1985-01-01 0.932319998741150 1986-01-01 0.946510016918182 1987-01-01 0.929539978504181 1988-01-01 0.921559989452362 1989-01-01 0.919409990310669 1990-01-01 0.934880018234253 1992-01-01 0.991190016269684 1993-01-01 0.995729982852936 1994-01-01 1.023779988288880 1995-01-01 1.062319993972780 1996-01-01 1.099779963493350 1997-01-01 1.101009964942930 1998-01-01 1.083709955215450 1999-01-01 1.038669943809510 2000-01-01 1.017660021781920 2001-01-01 1.010910034179690 2003-01-01 1.027619957923890 2004-01-01 1.058680057525630 2005-01-01 1.094030022621150 2006-01-01 1.078430056571960 2007-01-01 1.047899961471560 2008-01-01 1.069409966468810 2009-01-01 1.044780015945430 2010-01-01 1.022989988327030 2011-01-01 0.978789985179901 2012-01-01 1.061550021171570 2013-01-01 1.051010012626650 2014-01-01 1.066509962081910 2015-01-01 1.079120039939880