# year value 1900 -0.01 1901 -0.35 1902 -0.1 1903 -0.16 1904 -1.09 1905 -0.98 1906 -0.36 1907 -0.52 1908 -0.36 1909 -0.73 1910 -0.72 1911 -0.8 1912 -0.07 1913 -0.39 1914 -0.31 1915 -0.24 1916 -0.48 1917 -0.71 1918 -0.85 1919 -0.08 1920 0.24 1921 -0.48 1922 -0.44 1923 -0.39 1924 -0.27 1925 0.02 1926 0.38 1927 0.15 1928 -0.12 1929 -0.11 1930 0.14 1931 0.12 1932 -0.05 1933 -0.46 1934 -0.51 1935 -0.36 1936 -0.24 1937 -0.14 1938 -0.26 1939 -0.2 1940 -0.43 1941 0.28 1942 0.56 1943 -0.22 1944 -0.19 1945 0.14 1946 0.16 1947 0.25 1948 -0.03 1949 0.07 1950 -0.16 1951 -0.39 1952 0.26 1953 0.09 1954 0.06 1955 -0.01 1956 -0.44 1957 -0.27 1958 0.45 1959 0.12 1960 -0.06 1961 0.3 1962 -0.11 1963 -0.13 1964 0.19 1965 -0.23 1966 0.1 1967 0.04 1968 -0.17 1969 0.28 1970 0.17 1971 -0.34 1972 -0.18 1973 0.64 1974 -0.4 1975 -0.23 1976 -0.33 1977 0.4 1978 0.1 1979 -0.1 1980 0.19 1981 0.17 1982 0.15 1983 1.02 1984 0.24 1985 -0.02 1986 0.15 1987 0.65 1988 0.64 1989 0.14 1990 0.18 1991 0.2 1992 0.57 1993 0.14 1994 0.19 1995 0.7 1996 0.2 1997 0.12 1998 1.38 1999 0.32 2000 0.15 2001 0.33 2002 0.35 2003 0.76 2004 0.49 2005 0.79 2006 0.63 2007 0.67 2008 0.16 2009 0.31 2010 1.09 2011 0.37 2012 0.55 2013 0.74 2014 0.7 2015 0.67 2016 1.39 2017 1.2 2018 0.52