Hurrell PC-Based North Atlantic Oscillation Index (SON)
  1899    1.21
  1900    0.49
  1901   -0.65
  1902   -0.69
  1903   -0.15
  1904   -0.35
  1905   -0.52
  1906   -0.50
  1907    0.00
  1908   -0.35
  1909   -0.73
  1910   -2.09
  1911    0.26
  1912   -0.32
  1913    0.70
  1914   -0.01
  1915   -2.81
  1916    0.47
  1917    1.70
  1918    0.63
  1919   -1.29
  1920   -0.15
  1921   -0.81
  1922   -1.30
  1923    1.75
  1924    0.60
  1925   -0.52
  1926   -0.14
  1927   -0.52
  1928    0.65
  1929    1.64
  1930    0.21
  1931   -0.04
  1932    1.14
  1933   -1.35
  1934    0.46
  1935    1.53
  1936    0.74
  1937   -0.37
  1938    2.31
  1939   -1.02
  1940    0.57
  1941   -1.43
  1942    0.41
  1943    0.07
  1944    0.37
  1945   -1.32
  1946   -0.44
  1947   -0.55
  1948    1.00
  1949   -0.10
  1950    1.01
  1951    0.02
  1952   -1.19
  1953    1.70
  1954    2.08
  1955   -1.05
  1956    0.57
  1957    0.37
  1958   -0.16
  1959   -0.18
  1960   -1.18
  1961    0.75
  1962   -0.19
  1963    1.11
  1964    0.08
  1965   -1.11
  1966   -0.71
  1967    1.89
  1968   -2.70
  1969    1.56
  1970    0.20
  1971   -0.06
  1972   -0.14
  1973   -1.05
  1974    0.27
  1975    0.52
  1976   -0.79
  1977    1.21
  1978    2.02
  1979    0.43
  1980   -0.95
  1981   -0.50
  1982    2.01
  1983    0.36
  1984    0.62
  1985   -0.66
  1986    2.26
  1987    0.09
  1988   -0.34
  1989    0.65
  1990   -0.13
  1991    0.58
  1992    0.54
  1993   -1.16
  1994   -0.47
  1995   -1.26
  1996   -0.09
  1997   -1.11
  1998   -1.15
  1999    0.55
  2000    0.71
  2001    0.58
  2002   -1.93
  2003   -0.10
  2004   -0.14
  2005   -0.11
  2006   -0.21
  2007   -0.28
  2008    1.08
  2009    0.42
  2010   -1.65
  2011    1.83
  2012    0.09
  2013    0.34
  2014   -0.67
  2015    0.49
  2016   -0.88
  2017    0.01
  2018   -0.21
  2019   -0.96
  2020    1.33
  2021   -0.91
  2022    0.13
  2023   -0.75
  2024   -1.42
  2025   -0.33