# year    value 
 1900 10.47016 
 1901 10.51143 
 1902 10.36408 
 1903 9.645973 
 1904 9.998617 
 1905 10.27382 
 1906 10.41224 
 1907 10.37036 
 1908 10.47924 
 1909 10.35073 
 1910 10.41594 
 1911 10.34374 
 1912 10.12798 
 1913 10.07202 
 1914 10.32497 
 1915 10.32946 
 1916 10.44151 
 1917 10.52151 
 1918 10.50605 
 1919 10.58376 
 1920 10.29677 
 1921  10.5018 
 1922 10.63634 
 1923 10.53802 
 1924 10.53068 
 1925 10.64898 
 1926  10.5299 
 1927 10.59598 
 1928 10.51475 
 1929 10.57643 
 1930 10.49544 
 1931 10.48842 
 1932 10.47718 
 1933 10.53821 
 1934 10.47398 
 1935 10.53515 
 1936 10.49566 
 1937 10.70936 
 1938 10.60823 
 1939 10.62249 
 1940 10.70204 
 1941 10.57176 
 1942 10.57756 
 1943 10.51204 
 1944 10.60765 
 1945 10.57354 
 1946 10.66811 
 1947 10.75107 
 1948 10.56314 
 1949 10.87368 
 1950 10.81437 
 1951 10.74747 
 1952 10.68081 
 1953 10.73357 
 1954  10.5242 
 1955 10.69596 
 1956 10.68003 
 1957 10.52663 
 1958  10.4478 
 1959 10.54334 
 1960 10.56995 
 1961 10.58004 
 1962 10.55037 
 1963 10.53137 
 1964 10.32042 
 1965 10.26254 
 1966 10.36992 
 1967 10.50286 
 1968 10.35433 
 1969 10.29612 
 1970 10.44599 
 1971 10.61104 
 1972 10.59546 
 1973 10.59579 
 1974 10.53888 
 1975 10.34957 
 1976 10.65227 
 1977 10.75844 
 1978 10.80317 
 1979 10.80655 
 1980 10.79491 
 1981 11.00368 
 1982 10.61803 
 1983 10.29372 
 1984 10.73134 
 1985  10.7913 
 1986 10.93746 
 1987 10.87491 
 1988 10.95094 
 1989 11.13145 
 1990 11.00667 
 1991 11.19444 
 1992 10.37203 
 1993 10.56947 
 1994 11.10751 
 1995 11.05097 
 1996 11.12253 
 1997 11.21818 
 1998 11.51406 
 1999  11.3375 
 2000 11.58918 
 2001 11.47519 
 2002 11.52414 
 2003 11.71214 
 2004 11.62163 
 2005 11.54369