# year    value 
 1900    -0.45 
 1901    -0.73 
 1902    -0.33 
 1903    -0.46 
 1904    -0.91 
 1905    -0.59 
 1906    -0.25 
 1907    -0.55 
 1908    -0.92 
 1909    -0.26 
 1910     -0.1 
 1911     -0.8 
 1912    -0.31 
 1913    -0.46 
 1914    -0.24 
 1915     0.19 
 1916    -0.23 
 1917    -0.52 
 1918     -0.6 
 1919    -0.23 
 1920     -0.3 
 1921    -0.31 
 1922     -0.6 
 1923     -0.7 
 1924    -0.12 
 1925     -0.6 
 1926    -0.15 
 1927    -0.36 
 1928    -0.35 
 1929    -0.63 
 1930     -0.2 
 1931    -0.09 
 1932    -0.49 
 1933    -0.37 
 1934        0 
 1935    -0.49 
 1936    -0.01 
 1937    -0.29 
 1938     -0.1 
 1939    -0.37 
 1940     0.14 
 1941        0 
 1942     0.25 
 1943    -0.42 
 1944     0.14 
 1945     0.06 
 1946    -0.32 
 1947     0.11 
 1948    -0.02 
 1949    -0.22 
 1950    -0.09 
 1951    -0.15 
 1952    -0.06 
 1953    -0.23 
 1954    -0.21 
 1955     -0.1 
 1956    -0.35 
 1957    -0.03 
 1958     0.19 
 1959     0.17 
 1960    -0.18 
 1961    -0.06 
 1962    -0.03 
 1963    -0.06 
 1964     -0.2 
 1965    -0.14 
 1966     0.06 
 1967     -0.2 
 1968    -0.11 
 1969     0.23 
 1970     0.18 
 1971    -0.14 
 1972     0.12 
 1973     0.41 
 1974    -0.04 
 1975      0.1 
 1976     -0.2 
 1977      0.2 
 1978     0.15 
 1979     0.23 
 1980     0.28 
 1981     0.19 
 1982      0.2 
 1983     0.35 
 1984     0.13 
 1985      0.1 
 1986     0.28 
 1987     0.52 
 1988     0.58 
 1989     0.15 
 1990     0.35 
 1991      0.5 
 1992     0.39 
 1993     0.44 
 1994     0.19 
 1995     0.73 
 1996     0.56 
 1997     0.52 
 1998     1.05 
 1999      0.6 
 2000     0.28 
 2001     0.55 
 2002     0.65 
 2003     0.62 
 2004      0.4 
 2005      0.9 
 2006      0.7 
 2007     0.42 
 2008     0.59 
 2009     0.82 
 2010      0.8 
 2011     0.61 
 2012     0.52 
 2013     0.73 
 2014     0.77 
 2015     1.13 
 2016     1.08 
 2017     1.25 
 2018     0.66