# year value 1940 -0.5658178 1941 -0.5267546 1942 -0.5526886 1943 -0.5300467 1944 -0.5098982 1945 -0.5420271 1946 -0.569914 1947 -0.5346818 1948 -0.4941168 1949 -0.4956693 1950 -0.4991784 1951 -0.5210491 1952 -0.5513347 1953 -0.512336 1954 -0.5476592 1955 -0.5181767 1956 -0.5261661 1957 -0.5151854 1958 -0.5592201 1959 -0.4946003 1960 -0.5059734 1961 -0.5148312 1962 -0.5102829 1963 -0.623212 1964 -0.7876692 1965 -0.758737 1966 -0.6836445 1967 -0.6814814 1968 -0.7037226 1969 -0.7012265 1970 -0.6053397 1971 -0.5209875 1972 -0.5191308 1973 -0.49467 1974 -0.4838143 1975 -0.5239988 1976 -0.4815966 1977 -0.4451286 1978 -0.3724463 1979 -0.3330888 1980 -0.3004419 1981 -0.2425664 1982 -0.3865002 1983 -0.5756472 1984 -0.4022579 1985 -0.3643534 1986 -0.3149656 1987 -0.2399402 1988 -0.1298027 1989 -0.1036855 1990 -0.05014759 1991 -0.1297191 1992 -0.4757653 1993 -0.3538142 1994 -0.2199662 1995 -0.1419005 1996 -0.02734016 1997 0.04699113 1998 0.1164385 1999 0.09851211 2000 0.2171249 2001 0.3029367 2002 0.3069401 2003 0.3330348 2004 0.339415 2005 1.163071