# year    value 
 1901 -9.307602 
 1902 -10.57069 
 1903 -9.26987 
 1904 -9.119254 
 1905 -9.425244 
 1906 -9.110512 
 1907 -9.215299 
 1908 -9.344855 
 1909 -9.27542 
 1910 -9.60273 
 1911 -8.972595 
 1912 -9.789819 
 1913 -9.645352 
 1914 -9.333916 
 1915 -9.908957 
 1916 -9.069096 
 1917 -9.657873 
 1918 -9.260489 
 1919 -9.264635 
 1920 -9.76722 
 1921 -8.971676 
 1922 -9.467992 
 1923 -8.336234 
 1924 -8.368689 
 1925 -8.709645 
 1926 -8.521852 
 1927 -8.948598 
 1928 -8.785523 
 1929 -8.525807 
 1930 -8.708263 
 1931 -7.978124 
 1932 -9.077629 
 1933 -9.265818 
 1934 -8.333293 
 1935  -9.3003 
 1936 -8.716447 
 1937 -7.997486 
 1938 -7.71311 
 1939 -8.867651 
 1940 -8.920795 
 1941 -9.27669 
 1942 -8.759719 
 1943 -7.528268 
 1944 -8.093076 
 1945 -8.828057 
 1946 -9.357514 
 1947 -7.719601 
 1948 -7.866029 
 1949 -8.539195 
 1950 -9.322762 
 1951 -8.170561 
 1952 -9.466866 
 1953 -8.656178 
 1954 -8.206893 
 1955 -9.329511 
 1956 -10.18688 
 1957 -9.41465 
 1958 -9.630812 
 1959 -8.747567 
 1960 -9.697173 
 1961 -9.255626 
 1962 -9.012864 
 1963 -8.892817 
 1964 -9.497917 
 1965 -9.829602 
 1966 -9.761896 
 1967 -8.041437 
 1968 -10.17775 
 1969 -9.062747 
 1970 -9.210138 
 1971 -8.731313 
 1972 -10.30489 
 1973 -9.032085 
 1974 -10.05201 
 1975 -9.169155 
 1976 -9.42619 
 1977 -9.421337 
 1978 -8.893709 
 1979 -9.199169 
 1980 -9.148245 
 1981  -8.0569 
 1982 -10.3029 
 1983 -8.444068 
 1984 -9.633755 
 1985 -8.747724 
 1986 -9.046609 
 1987 -9.405209 
 1988 -8.605767 
 1989 -9.434759 
 1990 -9.913052 
 1991  -8.2008 
 1992 -10.28222 
 1993 -9.225085 
 1994 -8.615647 
 1995 -7.954495 
 1996 -8.751622 
 1997 -8.211693 
 1998 -9.162558 
 1999 -8.489529 
 2000 -8.713161 
 2001 -8.108681 
 2002 -7.966178 
 2003 -7.576478 
 2004 -8.164992 
 2005 -6.816862 
 2006 -7.999612 
 2007 -7.333787 
 2008 -7.532329 
 2009 -7.832829 
 2010 -7.126062 
 2011 -7.554861 
 2012 -7.703182 
 2013 -7.67271 
 2014 -8.075073 
 2015 -7.737015 
 2016 -7.428415 
 2017 -7.726055 
 2018 -7.31094