# year value 1900 2.286022 1901 2.055645 1902 2.062284 1903 1.873369 1904 1.84394 1905 1.972879 1906 2.011186 1907 2.052069 1908 2.109814 1909 2.099833 1910 2.098284 1911 2.165093 1912 2.126129 1913 2.119346 1914 2.150843 1915 2.146103 1916 2.242371 1917 2.171875 1918 2.18991 1919 2.124583 1920 2.199142 1921 2.252914 1922 2.224641 1923 2.268758 1924 2.256498 1925 2.259948 1926 2.198518 1927 2.298776 1928 2.331655 1929 2.298575 1930 2.291301 1931 2.221906 1932 2.300732 1933 2.262605 1934 2.162132 1935 2.256301 1936 2.299558 1937 2.382711 1938 2.353843 1939 2.343201 1940 2.397613 1941 2.334336 1942 2.406381 1943 2.386503 1944 2.401459 1945 2.365077 1946 2.330574 1947 2.339665 1948 2.299069 1949 2.466429 1950 2.360116 1951 2.42949 1952 2.378172 1953 2.316003 1954 2.39099 1955 2.361032 1956 2.386965 1957 2.495744 1958 2.357557 1959 2.459544 1960 2.492092 1961 2.458095 1962 2.397489 1963 2.414171 1964 2.027751 1965 2.109547 1966 2.170976 1967 2.197751 1968 2.292494 1969 2.256544 1970 2.306801 1971 2.438493 1972 2.467085 1973 2.4109 1974 2.411283 1975 2.430344 1976 2.461629 1977 2.446239 1978 2.505021 1979 2.532438 1980 2.590283 1981 2.723453 1982 2.651602 1983 2.405431 1984 2.544386 1985 2.555074 1986 2.55455 1987 2.643073 1988 2.801843 1989 2.67047 1990 2.852475 1991 2.753827 1992 2.466112 1993 2.598198 1994 2.549177 1995 2.628224 1996 2.802234 1997 2.88337 1998 2.936908 1999 2.934783 2000 3.018096 2001 3.023731 2002 3.143202 2003 3.08383 2004 3.067474 2005 3.218859