# year    value 
 1900 9.449533 
 1901 9.394547 
 1902 9.383343 
 1903 8.937394 
 1904 9.112411 
 1905 9.259935 
 1906 9.311005 
 1907 9.259141 
 1908 9.316544 
 1909 9.335069 
 1910  9.35939 
 1911 9.366408 
 1912 9.324773 
 1913 9.188325 
 1914 9.337623 
 1915 9.464691 
 1916 9.549436 
 1917 9.549815 
 1918 9.508781 
 1919 9.519992 
 1920 9.525949 
 1921  9.50553 
 1922 9.573903 
 1923 9.509353 
 1924 9.503025 
 1925 9.508902 
 1926 9.526087 
 1927 9.586871 
 1928 9.604746 
 1929 9.468843 
 1930 9.451826 
 1931 9.476674 
 1932 9.506927 
 1933 9.401276 
 1934 9.424553 
 1935 9.501237 
 1936 9.636884 
 1937 9.560184 
 1938 9.625123 
 1939 9.563234 
 1940 9.534806 
 1941  9.50719 
 1942 9.542377 
 1943 9.565139 
 1944 9.613308 
 1945 9.562803 
 1946 9.570409 
 1947 9.611415 
 1948 9.632664 
 1949 9.643949 
 1950 9.608444 
 1951  9.57726 
 1952 9.569715 
 1953 9.556948 
 1954 9.588134 
 1955 9.608874 
 1956 9.573947 
 1957 9.539297 
 1958  9.58921 
 1959 9.583787 
 1960 9.638617 
 1961 9.498942 
 1962  9.46326 
 1963 9.416427 
 1964 9.249482 
 1965 9.326077 
 1966 9.397985 
 1967 9.364188 
 1968 9.375804 
 1969 9.347619 
 1970 9.518858 
 1971 9.533628 
 1972 9.647103 
 1973 9.548131 
 1974 9.604022 
 1975 9.587765 
 1976 9.566654 
 1977 9.606565 
 1978 9.679341 
 1979 9.629317 
 1980 9.763992 
 1981 9.828213 
 1982 9.649585 
 1983 9.462769 
 1984 9.607937 
 1985 9.647936 
 1986 9.660856 
 1987 9.769361 
 1988 9.868363 
 1989 9.927679 
 1990 10.00057 
 1991 9.962626 
 1992 9.463901 
 1993 9.710341 
 1994 9.677669 
 1995 9.814686 
 1996 9.927822 
 1997 10.01747 
 1998 10.13972 
 1999 10.12632 
 2000 10.12608 
 2001 10.23082 
 2002 10.30042 
 2003 10.25591 
 2004 10.22439 
 2005 10.32875