# year    value 
 1901 10.73933 
 1902 10.83971 
 1903 10.42837 
 1904 10.79411 
 1905 10.57538 
 1906 10.56388 
 1907 10.16404 
 1908 10.28052 
 1909 10.41042 
 1910 10.31792 
 1911 10.27197 
 1912 10.57664 
 1913 10.61369 
 1914 10.76252 
 1915 10.18677 
 1916  10.8847 
 1917  10.4533 
 1918 10.43834 
 1919 11.20257 
 1920 10.71342 
 1921 10.76429 
 1922 10.78002 
 1923 10.49071 
 1924 10.28537 
 1925 10.45339 
 1926 10.48002 
 1927 10.59818 
 1928 10.40003 
 1929 10.61934 
 1930 10.68103 
 1931 10.18397 
 1932 10.88705 
 1933 10.70592 
 1934 10.55693 
 1935 10.83114 
 1936 10.21309 
 1937 10.33844 
 1938 10.77692 
 1939 10.38334 
 1940 10.24832 
 1941 10.06512 
 1942 10.41618 
 1943  10.6945 
 1944 10.74948 
 1945    10.99 
 1946 10.65299 
 1947 10.70857 
 1948 10.36099 
 1949 10.51427 
 1950 10.65174 
 1951 10.92308 
 1952  10.9102 
 1953 10.97258 
 1954 10.73476 
 1955  10.6476 
 1956 10.10541 
 1957 11.09499 
 1958  10.8645 
 1959 10.07056 
 1960 10.73789 
 1961 10.52982 
 1962 10.90377 
 1963 10.49152 
 1964 10.46886 
 1965 10.42673 
 1966 11.10562 
 1967 11.01072 
 1968 10.99678 
 1969 10.83235 
 1970 11.01047 
 1971 10.36434 
 1972 10.47291 
 1973 10.74667 
 1974 10.88901 
 1975 10.72999 
 1976 10.33385 
 1977 10.90979 
 1978   11.286 
 1979 11.03401 
 1980 11.00755 
 1981 11.20746 
 1982 11.19672 
 1983 11.05531 
 1984 10.30992 
 1985 10.83345 
 1986 10.89639 
 1987 11.06123 
 1988 10.74935 
 1989 11.12045 
 1990 10.73982 
 1991 11.26571 
 1992 10.76418 
 1993 10.83762 
 1994 11.03978 
 1995 10.98045 
 1996 11.02584 
 1997 11.22647 
 1998 11.45049 
 1999 11.05801 
 2000 10.75307 
 2001 10.63879 
 2002 10.71592 
 2003 11.26822 
 2004 11.03508 
 2005 10.75453 
 2006 10.70166 
 2007 10.99111 
 2008 10.96322 
 2009 11.70019 
 2010 11.38542 
 2011 11.16064 
 2012 11.16652 
 2013 11.44108 
 2014 11.04875 
 2015 11.92348 
 2016 11.45164 
 2017 11.56439 
 2018 11.61412