Year Ratio 1971-01-01 0.500320017337799 1972-01-01 0.539820015430450 1973-01-01 0.539290010929108 1974-01-01 0.550080001354218 1975-01-01 0.575789988040924 1976-01-01 0.568859994411469 1977-01-01 0.604019999504089 1978-01-01 0.664210021495819 1979-01-01 0.780499994754791 1980-01-01 0.875400006771088 1981-01-01 0.986599981784821 1982-01-01 0.793250024318695 1983-01-01 0.853439986705780 1984-01-01 0.887570023536682 1985-01-01 0.951160013675690 1986-01-01 0.992760002613068 1987-01-01 1.123980045318600 1988-01-01 1.233809947967530 1989-01-01 1.190950036048890 1990-01-01 1.274070024490360 1991-01-01 1.114629983901980 1992-01-01 1.100589990615840 1993-01-01 1.111709952354430 1994-01-01 1.053779959678650 1996-01-01 0.950079977512360 1997-01-01 0.969730019569397 2000-01-01 1.145810008049010 2002-01-01 1.033939957618710 2003-01-01 1.124819993972780 2004-01-01 1.131450057029720 2005-01-01 1.086899995803830 2006-01-01 1.143210053443910 2007-01-01 1.121250033378600 2008-01-01 1.116580009460450 2009-01-01 1.107740044593810 2010-01-01 1.137050032615660 2011-01-01 1.158669948577880 2012-01-01 1.152770042419430 2015-01-01 1.088050007820130 2016-01-01 1.072239995002750