# year value 1900 -0.12 1901 -0.07 1902 -2.8 1903 -0.06 1904 0.74 1905 0.81 1906 0.55 1907 -0.19 1908 -0.86 1909 -1.53 1910 -0.61 1911 -0.89 1912 -0.25 1913 0.02 1914 -1.28 1915 0.24 1916 -0.91 1917 -1.21 1918 -1.29 1919 -1.21 1920 1.37 1921 0.64 1922 -0.29 1923 -0.96 1924 0.33 1925 -0.54 1926 0.83 1927 -0.94 1928 -0.5 1929 -1.23 1930 -0.43 1931 -0.39 1932 0.85 1933 -0.59 1934 -0.01 1935 -0.17 1936 0.23 1937 0.05 1938 1.49 1939 0.17 1940 1.07 1941 -1.2 1942 -0.75 1943 2.01 1944 0.63 1945 0.08 1946 -0.01 1947 0.67 1948 0.47 1949 0.56 1950 0.52 1951 0.31 1952 -0.13 1953 1.64 1954 0.79 1955 -0.74 1956 -0.48 1957 0.05 1958 -0.78 1959 0.05 1960 -0.13 1961 -0.43 1962 0.92 1963 -0.73 1964 -2.08 1965 0.6 1966 -1.36 1967 1.1 1968 0.85 1969 -0.95 1970 -0.24 1971 -0.24 1972 -0.47 1973 0.47 1974 0.22 1975 1.24 1976 0.64 1977 0.6 1978 -0.37 1979 -0.57 1980 0.51 1981 0.83 1982 -0.09 1983 -0.02 1984 0.44 1985 -0.46 1986 0.26 1987 -0.38 1988 0.85 1989 1.03 1990 2.72 1991 0.93 1992 0.18 1993 1.2 1994 0.85 1995 2.06 1996 1.37 1997 1.88 1998 1.12 1999 0.35 2000 1.9 2001 0.65 2002 1.41 2003 1.92 2004 0.58 2005 1.71 2006 1.02 2007 2.24 2008 1.36 2009 0.88 2010 2.5 2011 2.96 2012 1.63 2013 1 2014 2.91 2015 2.57 2016 3.39 2017 2.57 2018 0.98