# year    value 
 1901 -12.25949 
 1902 -14.21135 
 1903 -13.1707 
 1904 -12.50368 
 1905 -12.24323 
 1906 -11.90829 
 1907 -12.75806 
 1908 -13.33797 
 1909 -13.61701 
 1910 -13.38535 
 1911 -13.47345 
 1912 -12.54359 
 1913 -12.46463 
 1914 -13.21622 
 1915 -11.89288 
 1916 -13.4987 
 1917 -12.26979 
 1918 -13.15463 
 1919 -13.12368 
 1920 -12.68447 
 1921 -12.79336 
 1922 -13.18904 
 1923 -12.80558 
 1924 -12.54066 
 1925 -12.77792 
 1926 -11.2055 
 1927 -12.93674 
 1928 -12.75838 
 1929 -12.92041 
 1930 -12.52424 
 1931 -13.13735 
 1932 -11.82054 
 1933 -12.95751 
 1934 -12.52009 
 1935 -13.00739 
 1936 -12.38485 
 1937 -12.80061 
 1938 -11.61816 
 1939 -12.00141 
 1940 -10.98283 
 1941 -12.45819 
 1942 -13.10933 
 1943 -10.33239 
 1944 -12.00333 
 1945 -11.87507 
 1946 -13.08252 
 1947 -11.57663 
 1948 -11.77724 
 1949 -11.81847 
 1950 -12.95644 
 1951 -12.83848 
 1952 -12.75057 
 1953  -11.134 
 1954 -12.05382 
 1955 -13.60188 
 1956 -13.32226 
 1957 -12.33724 
 1958 -13.06575 
 1959 -12.54131 
 1960 -12.44495 
 1961 -13.20946 
 1962 -11.80257 
 1963 -13.0973 
 1964 -14.47611 
 1965 -11.88605 
 1966 -13.79805 
 1967 -11.72072 
 1968 -11.04502 
 1969 -12.86404 
 1970 -12.2628 
 1971 -12.98558 
 1972 -13.15353 
 1973 -12.44623 
 1974 -12.30895 
 1975 -11.5639 
 1976 -12.75461 
 1977 -12.50374 
 1978 -11.94057 
 1979 -12.68906 
 1980 -12.34442 
 1981 -10.68114 
 1982 -12.73808 
 1983 -12.0985 
 1984 -11.66333 
 1985 -13.20325 
 1986 -12.70043 
 1987 -13.07416 
 1988 -11.31782 
 1989 -11.43938 
 1990 -8.916918 
 1991 -11.3156 
 1992 -11.9548 
 1993 -10.96714 
 1994 -11.66159 
 1995 -11.03562 
 1996 -11.25436 
 1997 -10.71002 
 1998 -11.66604 
 1999 -12.53466 
 2000 -10.80032 
 2001 -11.59288 
 2002 -10.83928 
 2003 -10.73504 
 2004 -11.45644 
 2005 -10.0075 
 2006 -12.17195 
 2007 -10.52155 
 2008 -10.68751 
 2009 -11.26522 
 2010 -10.44209 
 2011 -9.811411 
 2012 -11.24822 
 2013 -11.28523 
 2014 -9.817158 
 2015 -10.35537 
 2016 -9.168548 
 2017 -9.683318 
 2018 -10.83105