# year    value 
 1900     0.26 
 1901     0.12 
 1902     0.41 
 1903    -1.02 
 1904     -0.5 
 1905    -1.79 
 1906    -0.28 
 1907    -1.17 
 1908    -0.37 
 1909     -0.4 
 1910    -0.32 
 1911    -0.56 
 1912    -0.33 
 1913    -0.79 
 1914    -0.25 
 1915     0.18 
 1916     0.06 
 1917    -1.06 
 1918    -0.72 
 1919    -0.03 
 1920    -0.64 
 1921     0.45 
 1922     0.44 
 1923    -0.15 
 1924     0.08 
 1925      0.1 
 1926     -0.7 
 1927    -0.68 
 1928    -0.22 
 1929     0.73 
 1930     0.02 
 1931    -0.13 
 1932     0.27 
 1933     -0.6 
 1934    -0.73 
 1935    -0.01 
 1936    -0.95 
 1937    -0.85 
 1938     0.87 
 1939    -0.41 
 1940    -0.05 
 1941     1.02 
 1942     0.65 
 1943     0.03 
 1944     0.42 
 1945    -0.02 
 1946     0.28 
 1947     0.66 
 1948     0.41 
 1949    -0.11 
 1950    -0.03 
 1951    -0.57 
 1952     0.15 
 1953     0.46 
 1954    -0.55 
 1955    -0.36 
 1956     0.06 
 1957    -0.75 
 1958     0.43 
 1959     0.33 
 1960    -0.81 
 1961      0.7 
 1962     0.01 
 1963     0.26 
 1964     0.41 
 1965    -0.21 
 1966     0.01 
 1967     0.08 
 1968    -0.05 
 1969     0.04 
 1970    -0.37 
 1971    -0.21 
 1972    -0.06 
 1973     0.55 
 1974     0.29 
 1975     0.22 
 1976    -0.65 
 1977     0.65 
 1978     0.24 
 1979    -0.59 
 1980     0.18 
 1981     0.66 
 1982    -0.06 
 1983     -0.1 
 1984     0.19 
 1985        0 
 1986        0 
 1987    -0.01 
 1988    -0.02 
 1989     0.11 
 1990     0.28 
 1991     0.04 
 1992    -0.12 
 1993        0 
 1994     0.52 
 1995     0.18 
 1996    -0.11 
 1997     0.78 
 1998     0.73 
 1999     0.69 
 2000      1.3 
 2001     1.36 
 2002     1.39 
 2003     0.38 
 2004     1.54 
 2005     1.01 
 2006        1 
 2007     1.31 
 2008     1.92 
 2009     1.42 
 2010     0.97 
 2011     0.78 
 2012     1.33 
 2013     1.48 
 2014     1.16 
 2015     1.25 
 2016     1.95 
 2017     1.61 
 2018     2.22