# year    value 
 1940 -0.368389 
 1941 -0.3568171 
 1942 -0.3832138 
 1943 -0.440047 
 1944 -0.3677561 
 1945 -0.3587192 
 1946 -0.3711288 
 1947 -0.3616724 
 1948 -0.3428174 
 1949 -0.3129914 
 1950 -0.3426618 
 1951 -0.3569563 
 1952 -0.3858962 
 1953 -0.3352767 
 1954 -0.3315173 
 1955 -0.3461173 
 1956 -0.329334 
 1957 -0.3189993 
 1958 -0.3248927 
 1959 -0.2832656 
 1960 -0.3201065 
 1961 -0.3018264 
 1962 -0.35159 
 1963 -0.4216528 
 1964 -0.5513969 
 1965 -0.4771377 
 1966 -0.4385774 
 1967 -0.3589137 
 1968 -0.3679932 
 1969 -0.3724795 
 1970 -0.3546935 
 1971 -0.2796331 
 1972 -0.250457 
 1973 -0.2817779 
 1974 -0.2870515 
 1975 -0.303012 
 1976 -0.3059225 
 1977 -0.2143275 
 1978 -0.2322705 
 1979 -0.1639325 
 1980 -0.1505723 
 1981 -0.1177917 
 1982 -0.206347 
 1983 -0.2905083 
 1984 -0.199289 
 1985 -0.1677764 
 1986 -0.1826069 
 1987 -0.1460947 
 1988 -0.09834147 
 1989 -0.04163187 
 1990 -0.03044169 
 1991 -0.07405693 
 1992 -0.2832814 
 1993 -0.1965431 
 1994 -0.1191503 
 1995 -0.07477171 
 1996 -0.01620744 
 1997 0.03757444 
 1998 0.0798235 
 1999 0.09307501 
 2000 0.09473584 
 2001 0.1773663 
 2002 0.2039664 
 2003 0.1948002 
 2004 0.1514574 
 2005 -0.09378461