# year    value 
 1901 -25.91514 
 1902 -26.15635 
 1903 -25.64203 
 1904 -25.90123 
 1905 -25.03333 
 1906 -26.31751 
 1907 -26.03952 
 1908 -26.40177 
 1909 -26.36038 
 1910 -25.53702 
 1911 -26.52562 
 1912 -25.72159 
 1913 -26.39577 
 1914 -25.06467 
 1915 -25.69171 
 1916 -25.9629 
 1917 -26.94465 
 1918 -26.54973 
 1919 -27.0253 
 1920 -25.26494 
 1921 -25.38276 
 1922 -26.58986 
 1923 -25.28819 
 1924 -25.53483 
 1925 -24.94877 
 1926 -24.7359 
 1927 -25.7412 
 1928 -24.90703 
 1929 -24.80835 
 1930 -25.05897 
 1931 -25.51303 
 1932 -24.51147 
 1933 -25.76302 
 1934 -24.39299 
 1935 -23.88971 
 1936 -25.97169 
 1937 -23.58302 
 1938 -24.82505 
 1939 -24.99328 
 1940 -23.90482 
 1941 -26.04785 
 1942 -25.17472 
 1943 -24.1185 
 1944 -23.31292 
 1945 -23.63933 
 1946 -26.2688 
 1947 -25.52023 
 1948 -24.75075 
 1949 -25.41798 
 1950 -26.11412 
 1951 -26.21566 
 1952 -24.93585 
 1953 -25.09874 
 1954 -25.48361 
 1955 -24.95834 
 1956 -26.42064 
 1957 -24.67321 
 1958 -25.53726 
 1959 -25.00966 
 1960 -25.44606 
 1961 -24.28628 
 1962 -24.4052 
 1963 -24.41133 
 1964 -24.80944 
 1965 -26.10201 
 1966 -27.93524 
 1967 -25.68683 
 1968 -24.88168 
 1969 -27.27353 
 1970 -24.95177 
 1971 -25.94581 
 1972 -26.42348 
 1973 -24.92787 
 1974 -26.06751 
 1975 -25.24447 
 1976 -25.58245 
 1977 -25.11955 
 1978 -24.72973 
 1979 -27.25663 
 1980 -24.31436 
 1981 -23.06163 
 1982 -24.87658 
 1983 -24.72042 
 1984 -24.35724 
 1985 -26.19021 
 1986 -24.23169 
 1987 -25.82629 
 1988 -24.52315 
 1989 -23.91284 
 1990 -25.66253 
 1991 -25.17658 
 1992 -24.42084 
 1993 -23.37148 
 1994 -26.12632 
 1995 -22.97221 
 1996 -24.36084 
 1997 -24.87944 
 1998 -25.35913 
 1999 -24.46399 
 2000 -23.65565 
 2001 -25.03773 
 2002 -24.00346 
 2003 -23.96098 
 2004 -23.77797 
 2005 -24.0367 
 2006 -23.58292 
 2007 -22.58079 
 2008 -23.09296 
 2009 -24.14663 
 2010 -24.43195 
 2011 -23.88597 
 2012 -22.67665 
 2013 -24.76147 
 2014 -23.3499 
 2015 -22.79251 
 2016 -21.67108 
 2017 -23.11677 
 2018 -22.5766