# year    value 
 1900 5.009475 
 1901 4.514171 
 1902 4.516033 
 1903 4.309315 
 1904 4.282582 
 1905 4.365405 
 1906 4.593525 
 1907 4.502853 
 1908 4.558965 
 1909 4.528122 
 1910 4.603606 
 1911 4.530468 
 1912 4.658196 
 1913   4.5783 
 1914 4.620797 
 1915 4.579156 
 1916  4.60139 
 1917 4.666006 
 1918 4.703184 
 1919 4.650527 
 1920  4.69475 
 1921 4.603526 
 1922 4.651484 
 1923 4.659116 
 1924 4.706519 
 1925 4.650232 
 1926 4.720906 
 1927 4.699095 
 1928 4.717995 
 1929 4.702941 
 1930 4.714772 
 1931 4.688939 
 1932  4.66206 
 1933 4.574212 
 1934 4.705533 
 1935 4.762648 
 1936 4.702236 
 1937 4.754669 
 1938 4.705228 
 1939 4.858785 
 1940 4.834545 
 1941 4.790441 
 1942 4.781067 
 1943 4.758964 
 1944 4.825303 
 1945 4.819855 
 1946 4.751813 
 1947 4.750714 
 1948 4.873819 
 1949 4.850711 
 1950 4.830424 
 1951 4.832834 
 1952 4.716657 
 1953  4.83374 
 1954 4.822687 
 1955 4.826437 
 1956 4.760461 
 1957  4.86946 
 1958 4.814233 
 1959 4.796132 
 1960 4.772681 
 1961 4.864024 
 1962  4.83484 
 1963 4.787923 
 1964 4.501796 
 1965  4.64248 
 1966 4.649363 
 1967 4.694077 
 1968 4.798306 
 1969 4.759804 
 1970 4.679825 
 1971 4.924466 
 1972 4.930408 
 1973 4.884837 
 1974 4.863474 
 1975 5.001911 
 1976 4.917499 
 1977 5.005696 
 1978 4.982923 
 1979 4.962281 
 1980 4.936105 
 1981 5.076315 
 1982  5.05296 
 1983 4.841856 
 1984 4.897617 
 1985 5.054018 
 1986 5.041439 
 1987   5.0091 
 1988 5.095388 
 1989 5.102391 
 1990 5.143921 
 1991  5.16903 
 1992 4.913533 
 1993 4.976898 
 1994 5.059536 
 1995 5.126914 
 1996 5.121092 
 1997 5.218918 
 1998 5.268533 
 1999 5.380669 
 2000 5.277183 
 2001 5.493528 
 2002 5.445474 
 2003 5.482849 
 2004 5.380732 
 2005 5.469596