# year    value 
 1901  25.5776 
 1902 25.59133 
 1903 25.38761 
 1904 25.39541 
 1905 25.41169 
 1906 25.51354 
 1907 25.35952 
 1908 25.47747 
 1909 25.50941 
 1910 25.32667 
 1911  25.3563 
 1912 25.43179 
 1913 25.33632 
 1914  25.5134 
 1915 25.60374 
 1916 25.36846 
 1917  25.2457 
 1918 25.34362 
 1919  25.6148 
 1920 25.38679 
 1921  25.5199 
 1922 25.46913 
 1923 25.47896 
 1924 25.64821 
 1925  25.4436 
 1926 25.64308 
 1927 25.56711 
 1928 25.63803 
 1929 25.37411 
 1930 25.51337 
 1931 25.78838 
 1932 25.59439 
 1933 25.60067 
 1934 25.58153 
 1935 25.72896 
 1936 25.69859 
 1937 25.81876 
 1938 25.77145 
 1939  25.7733 
 1940 25.73973 
 1941 26.00243 
 1942  25.7819 
 1943 25.44774 
 1944 25.60624 
 1945 25.49308 
 1946 25.62244 
 1947 25.79741 
 1948 25.48976 
 1949 25.46751 
 1950 25.26693 
 1951 25.58785 
 1952 25.60343 
 1953 25.59209 
 1954 25.45473 
 1955 25.50777 
 1956 25.30896 
 1957 25.46737 
 1958 25.83131 
 1959 25.50904 
 1960 25.66212 
 1961 25.33717 
 1962 25.53305 
 1963  25.6714 
 1964 25.36711 
 1965 25.43235 
 1966 25.69111 
 1967 25.23726 
 1968 25.37182 
 1969 25.90445 
 1970 25.60888 
 1971 25.23722 
 1972 25.53747 
 1973 25.72332 
 1974 25.31859 
 1975 25.32045 
 1976 25.37486 
 1977 25.60068 
 1978    25.64 
 1979 25.88356 
 1980  25.8922 
 1981 25.72463 
 1982  25.6245 
 1983 25.78283 
 1984 25.69461 
 1985 25.73532 
 1986 25.70237 
 1987 26.17612 
 1988 25.90962 
 1989 25.59431 
 1990 26.02421 
 1991 25.85304 
 1992 25.56419 
 1993 25.85417 
 1994  25.7999 
 1995 25.96255 
 1996 25.98314 
 1997 26.00034 
 1998 26.43552 
 1999 26.05453 
 2000 25.97972 
 2001 26.21543 
 2002 26.32471 
 2003 26.34036 
 2004 26.31101 
 2005 26.36996 
 2006  26.2956 
 2007 26.27022 
 2008 26.11959 
 2009 26.52616 
 2010   26.744 
 2011  26.2342 
 2012 26.24635 
 2013  26.2621 
 2014 26.30065 
 2015 26.41679 
 2016 26.61067 
 2017 26.40714 
 2018 26.33485