# year    value 
 1900        0 
 1901     -0.2 
 1902     0.11 
 1903    -0.28 
 1904    -0.55 
 1905    -0.54 
 1906    -0.21 
 1907    -0.63 
 1908     0.06 
 1909    -0.23 
 1910    -0.44 
 1911    -0.49 
 1912    -0.12 
 1913    -0.75 
 1914    -0.28 
 1915     -0.3 
 1916    -0.16 
 1917    -1.08 
 1918    -0.77 
 1919    -0.04 
 1920    -0.58 
 1921    -0.07 
 1922    -0.12 
 1923    -0.37 
 1924     0.02 
 1925    -0.16 
 1926    -0.34 
 1927    -0.28 
 1928     0.03 
 1929     0.01 
 1930    -0.29 
 1931    -0.03 
 1932    -0.29 
 1933    -0.16 
 1934    -0.38 
 1935    -0.14 
 1936     -0.1 
 1937     -0.1 
 1938    -0.02 
 1939    -0.32 
 1940     -0.3 
 1941     0.39 
 1942     0.28 
 1943    -0.33 
 1944    -0.18 
 1945    -0.14 
 1946     0.14 
 1947     0.09 
 1948    -0.09 
 1949    -0.05 
 1950     -0.2 
 1951     -0.2 
 1952     0.05 
 1953      0.1 
 1954    -0.01 
 1955    -0.08 
 1956    -0.17 
 1957    -0.39 
 1958     0.52 
 1959     0.12 
 1960    -0.15 
 1961     0.09 
 1962     -0.1 
 1963    -0.17 
 1964     0.23 
 1965    -0.35 
 1966     0.06 
 1967     -0.2 
 1968     -0.5 
 1969     0.47 
 1970     0.08 
 1971    -0.21 
 1972    -0.17 
 1973     0.48 
 1974    -0.11 
 1975     0.01 
 1976     -0.4 
 1977      0.1 
 1978     0.19 
 1979      0.2 
 1980     0.52 
 1981     0.26 
 1982        0 
 1983     0.34 
 1984     0.36 
 1985     0.21 
 1986     0.19 
 1987      0.4 
 1988     0.67 
 1989     0.09 
 1990      0.2 
 1991     0.49 
 1992     0.16 
 1993     0.17 
 1994     0.42 
 1995     0.46 
 1996     0.39 
 1997     0.16 
 1998     1.11 
 1999     0.65 
 2000      0.6 
 2001     0.72 
 2002     0.96 
 2003     0.87 
 2004     0.88 
 2005     0.88 
 2006     0.73 
 2007     0.79 
 2008     0.75 
 2009     0.83 
 2010     1.45 
 2011     0.67 
 2012     0.78 
 2013     0.96 
 2014     0.92 
 2015     0.99 
 2016     1.54 
 2017      1.1 
 2018     1.15