# year    value 
 1900 7.880635 
 1901 7.861229 
 1902 7.817213 
 1903 7.374403 
 1904  7.53913 
 1905 7.702497 
 1906  7.75606 
 1907 7.714653 
 1908 7.753478 
 1909 7.795939 
 1910 7.825494 
 1911 7.825799 
 1912 7.695779 
 1913 7.616162 
 1914 7.761098 
 1915 7.892748 
 1916  7.91122 
 1917 7.932662 
 1918  7.97473 
 1919 7.929646 
 1920 7.937545 
 1921 7.931012 
 1922 7.981547 
 1923 7.950555 
 1924 7.995318 
 1925 8.006777 
 1926 7.976532 
 1927 8.019009 
 1928 8.043663 
 1929 7.979747 
 1930 7.948975 
 1931 7.962436 
 1932 7.993012 
 1933 7.968943 
 1934 7.960728 
 1935 7.991648 
 1936 8.054613 
 1937 8.050903 
 1938 8.076181 
 1939 8.034571 
 1940 8.075257 
 1941 8.048861 
 1942 8.042242 
 1943 8.053628 
 1944 8.044469 
 1945 8.041677 
 1946 8.038818 
 1947 8.044603 
 1948 8.087527 
 1949 8.137538 
 1950 8.101135 
 1951 8.104752 
 1952 8.057995 
 1953 8.020651 
 1954 8.026281 
 1955 8.051318 
 1956 8.062024 
 1957 8.033706 
 1958  8.05965 
 1959 8.059039 
 1960 8.082904 
 1961  8.01799 
 1962 7.962297 
 1963   7.8918 
 1964  7.75124 
 1965 7.793416 
 1966 7.862815 
 1967  7.90746 
 1968 7.854704 
 1969 7.842938 
 1970 7.961735 
 1971 8.034458 
 1972 8.049968 
 1973  8.05183 
 1974 8.058815 
 1975 7.993471 
 1976 8.082649 
 1977 8.122362 
 1978 8.188304 
 1979 8.225502 
 1980  8.29741 
 1981 8.315666 
 1982 8.144197 
 1983 7.894732 
 1984 8.127045 
 1985 8.210531 
 1986 8.251263 
 1987  8.29101 
 1988 8.381681 
 1989 8.446976 
 1990 8.475578 
 1991  8.43062 
 1992 7.981841 
 1993 8.196098 
 1994 8.333263 
 1995 8.406417 
 1996 8.502414 
 1997 8.610815 
 1998 8.692892 
 1999 8.685739 
 2000 8.762486 
 2001 8.859545 
 2002 8.823287 
 2003 8.844238 
 2004  8.86377 
 2005 8.918803