# year value 1940 -0.4587178 1941 -0.4283681 1942 -0.4037765 1943 -0.4153408 1944 -0.3693 1945 -0.4118789 1946 -0.4537683 1947 -0.42201 1948 -0.3808797 1949 -0.3357777 1950 -0.4237986 1951 -0.3777208 1952 -0.3888229 1953 -0.4226199 1954 -0.3980244 1955 -0.4227142 1956 -0.3599559 1957 -0.3643496 1958 -0.3954249 1959 -0.3767004 1960 -0.3569179 1961 -0.3591197 1962 -0.4135666 1963 -0.5371939 1964 -0.7305752 1965 -0.5794429 1966 -0.5281604 1967 -0.5228637 1968 -0.5036211 1969 -0.5032006 1970 -0.4638359 1971 -0.3571472 1972 -0.3693004 1973 -0.3542144 1974 -0.3766208 1975 -0.3656852 1976 -0.3197392 1977 -0.3281418 1978 -0.2926293 1979 -0.2435267 1980 -0.1523272 1981 -0.1634963 1982 -0.293801 1983 -0.3905546 1984 -0.2630462 1985 -0.2532349 1986 -0.2536002 1987 -0.1680136 1988 -0.05296966 1989 -0.06142674 1990 0.01774312 1991 -0.1373865 1992 -0.3561631 1993 -0.2177042 1994 -0.2053479 1995 -0.1583358 1996 0.0001029422 1997 0.05072899 1998 0.09195331 1999 0.1032769 2000 0.1249085 2001 0.2231214 2002 0.2940951 2003 0.2000148 2004 0.2222902 2005 0.1411713