# year    value 
 1901 25.26584 
 1902 25.49202 
 1903 25.36838 
 1904 24.85722 
 1905 24.94394 
 1906 25.23428 
 1907 25.21639 
 1908  25.3358 
 1909 25.26652 
 1910 25.02933 
 1911 25.19016 
 1912 25.78779 
 1913 25.56438 
 1914 25.60546 
 1915 25.45797 
 1916 25.38661 
 1917  25.2079 
 1918 25.04043 
 1919 25.73241 
 1920   25.527 
 1921 25.09504 
 1922 25.34826 
 1923 25.20928 
 1924 25.34937 
 1925 25.31507 
 1926 25.87767 
 1927 25.44084 
 1928 25.20946 
 1929 25.43626 
 1930  25.4874 
 1931 25.69589 
 1932 25.50527 
 1933 25.30112 
 1934 25.03972 
 1935 25.32637 
 1936 25.43027 
 1937   25.544 
 1938 25.52165 
 1939 25.58683 
 1940 25.24595 
 1941 25.38906 
 1942 25.76915 
 1943 25.79632 
 1944 25.45814 
 1945 25.83751 
 1946 25.53476 
 1947 25.44906 
 1948 25.27652 
 1949 25.46439 
 1950 25.16768 
 1951 24.74506 
 1952 25.39581 
 1953 25.33075 
 1954 25.23637 
 1955 25.39435 
 1956 24.61829 
 1957 25.03937 
 1958 25.58358 
 1959 25.04921 
 1960 25.59436 
 1961 25.50213 
 1962  25.3609 
 1963 25.59892 
 1964 25.84604 
 1965 25.50248 
 1966 25.44592 
 1967 25.28183 
 1968 25.65332 
 1969 25.70666 
 1970 25.72858 
 1971 24.99422 
 1972 25.62841 
 1973 25.85591 
 1974 24.60639 
 1975 24.77693 
 1976 25.03155 
 1977 25.26441 
 1978 25.16707 
 1979 25.39734 
 1980 25.54755 
 1981 25.15557 
 1982 25.21237 
 1983 25.87993 
 1984  25.4107 
 1985 25.09253 
 1986 25.38254 
 1987 25.68955 
 1988 25.62251 
 1989 25.70224 
 1990 25.56952 
 1991 25.42929 
 1992  25.4566 
 1993 25.19717 
 1994 25.31165 
 1995 25.71743 
 1996 25.52856 
 1997 25.27132 
 1998 25.80211 
 1999 25.49395 
 2000 25.23167 
 2001  25.5247 
 2002 25.43054 
 2003 25.73176 
 2004 25.62766 
 2005 25.85539 
 2006 25.50748 
 2007 25.77164 
 2008 25.22236 
 2009 25.49054 
 2010 25.83125 
 2011 25.39448 
 2012 25.60441 
 2013 25.72683 
 2014 25.80265 
 2015 25.65825 
 2016 26.35144 
 2017 25.98489 
 2018 25.70275