# year    value 
 1900    -0.27 
 1901     -0.3 
 1902    -2.12 
 1903    -0.25 
 1904    -0.02 
 1905    -0.36 
 1906     0.04 
 1907    -0.45 
 1908    -0.69 
 1909     -0.2 
 1910    -0.38 
 1911      0.4 
 1912    -0.54 
 1913    -0.79 
 1914     0.03 
 1915    -0.94 
 1916     0.26 
 1917    -0.53 
 1918    -0.09 
 1919    -0.38 
 1920     -0.5 
 1921     0.18 
 1922     0.06 
 1923     1.35 
 1924     1.14 
 1925     0.58 
 1926     0.83 
 1927    -0.42 
 1928     0.23 
 1929      0.9 
 1930     0.29 
 1931      1.3 
 1932     -0.1 
 1933    -0.27 
 1934     1.02 
 1935    -0.05 
 1936     0.59 
 1937     1.47 
 1938     1.75 
 1939     0.34 
 1940     0.38 
 1941    -0.05 
 1942     0.37 
 1943     1.76 
 1944     1.22 
 1945     0.29 
 1946    -0.12 
 1947     1.61 
 1948     1.12 
 1949     0.67 
 1950     0.07 
 1951     1.03 
 1952    -0.17 
 1953     0.57 
 1954     0.93 
 1955    -0.26 
 1956    -1.15 
 1957    -0.22 
 1958    -0.33 
 1959     0.64 
 1960    -0.38 
 1961        0 
 1962     0.32 
 1963     0.23 
 1964    -0.38 
 1965    -0.49 
 1966    -0.39 
 1967     1.14 
 1968     -0.8 
 1969     0.25 
 1970      0.1 
 1971     0.44 
 1972       -1 
 1973     0.26 
 1974    -0.74 
 1975     0.08 
 1976    -0.15 
 1977    -0.04 
 1978     0.37 
 1979     0.09 
 1980     0.05 
 1981      1.2 
 1982    -0.99 
 1983     0.79 
 1984    -0.22 
 1985      0.6 
 1986     0.25 
 1987    -0.13 
 1988     0.41 
 1989    -0.18 
 1990    -0.52 
 1991     1.11 
 1992    -1.31 
 1993     0.08 
 1994      0.4 
 1995      1.5 
 1996     0.62 
 1997     1.09 
 1998     0.21 
 1999     0.72 
 2000     0.72 
 2001     1.08 
 2002     1.36 
 2003     1.73 
 2004     1.09 
 2005     2.61 
 2006     1.47 
 2007     2.26 
 2008     1.69 
 2009     1.38 
 2010     2.31 
 2011     1.95 
 2012     1.71 
 2013      1.5 
 2014      1.2 
 2015      1.7 
 2016      2.4 
 2017     1.92 
 2018     2.27