# year    value 
 1901  10.7024 
 1902 11.04161 
 1903 9.779314 
 1904 10.20822 
 1905 10.79109 
 1906 9.693533 
 1907 9.479566 
 1908 10.61519 
 1909 9.293941 
 1910 12.76137 
 1911 11.30333 
 1912 9.086473 
 1913 9.878887 
 1914  10.7416 
 1915 9.883509 
 1916 10.57715 
 1917 8.538658 
 1918 11.11643 
 1919 10.08702 
 1920 9.185149 
 1921 10.95613 
 1922 10.20738 
 1923 9.530357 
 1924 8.906543 
 1925 12.06581 
 1926 10.74765 
 1927 10.60695 
 1928 10.94082 
 1929 10.47089 
 1930 10.91481 
 1931 10.09272 
 1932 10.12456 
 1933 10.47961 
 1934 12.58291 
 1935 9.858124 
 1936 11.46588 
 1937 10.50516 
 1938 11.24821 
 1939 11.63396 
 1940 10.86205 
 1941 10.94003 
 1942 10.66906 
 1943 10.19775 
 1944  9.70133 
 1945 10.29244 
 1946 12.15131 
 1947 9.739553 
 1948 10.26758 
 1949 11.05073 
 1950 9.254699 
 1951 9.308095 
 1952 9.989074 
 1953 10.04364 
 1954 9.998131 
 1955 10.75061 
 1956 10.48631 
 1957 10.02474 
 1958 10.19325 
 1959 10.83094 
 1960 9.831324 
 1961 10.58335 
 1962 10.42187 
 1963 11.77595 
 1964 10.36063 
 1965 9.291085 
 1966 10.84651 
 1967 10.56605 
 1968  10.6267 
 1969 10.08347 
 1970  9.51873 
 1971 10.32434 
 1972 11.53343 
 1973 10.56785 
 1974 11.38799 
 1975 9.072648 
 1976 10.75447 
 1977 12.10256 
 1978 11.01292 
 1979  9.91014 
 1980 10.64908 
 1981 11.95697 
 1982 10.16313 
 1983 9.580716 
 1984 10.40376 
 1985 12.28026 
 1986 12.28944 
 1987 11.97267 
 1988 11.54624 
 1989 11.35818 
 1990 11.16938 
 1991 11.64565 
 1992 12.16788 
 1993 10.92605 
 1994 12.04546 
 1995   9.9705 
 1996 10.18004 
 1997 9.918966 
 1998 10.74909 
 1999  10.8082 
 2000 12.18837 
 2001 11.28851 
 2002 9.641039 
 2003 11.18682 
 2004  12.1729 
 2005 11.30718 
 2006 12.37672 
 2007 12.05178 
 2008 10.51468 
 2009 10.82422 
 2010 11.28182 
 2011 10.75488 
 2012 13.61452 
 2013  10.1378 
 2014 11.00263 
 2015  11.9588 
 2016 12.32005 
 2017 12.15993 
 2018 11.61255