Hurrell PC-Based North Atlantic Oscillation Index (SON)
  1899    1.25
  1900    0.34
  1901   -0.72
  1902   -0.83
  1903   -0.17
  1904   -0.42
  1905   -0.53
  1906   -0.59
  1907   -0.17
  1908   -0.53
  1909   -0.73
  1910   -2.06
  1911    0.17
  1912   -0.38
  1913    0.61
  1914   -0.14
  1915   -2.86
  1916    0.38
  1917    1.74
  1918    0.58
  1919   -1.27
  1920   -0.40
  1921   -0.96
  1922   -1.27
  1923    1.83
  1924    0.51
  1925   -0.45
  1926   -0.12
  1927   -0.47
  1928    0.55
  1929    1.56
  1930    0.27
  1931   -0.13
  1932    1.19
  1933   -1.42
  1934    0.44
  1935    1.45
  1936    0.66
  1937   -0.39
  1938    2.17
  1939   -1.08
  1940    0.58
  1941   -1.58
  1942    0.41
  1943    0.03
  1944    0.36
  1945   -1.40
  1946   -0.51
  1947   -0.51
  1948    1.04
  1949   -0.23
  1950    1.02
  1951   -0.09
  1952   -1.14
  1953    1.54
  1954    1.98
  1955   -0.98
  1956    0.54
  1957    0.38
  1958   -0.31
  1959   -0.34
  1960   -1.29
  1961    0.69
  1962   -0.21
  1963    1.06
  1964    0.07
  1965   -1.11
  1966   -0.62
  1967    1.87
  1968   -2.71
  1969    1.67
  1970    0.30
  1971    0.03
  1972   -0.09
  1973   -0.95
  1974    0.27
  1975    0.44
  1976   -0.91
  1977    1.22
  1978    2.01
  1979    0.39
  1980   -0.90
  1981   -0.37
  1982    1.91
  1983    0.48
  1984    0.52
  1985   -0.66
  1986    2.21
  1987   -0.04
  1988   -0.33
  1989    0.58
  1990   -0.12
  1991    0.63
  1992    0.52
  1993   -1.40
  1994   -0.40
  1995   -1.13
  1996    0.00
  1997   -1.03
  1998   -1.08
  1999    0.53
  2000    0.63
  2001    0.62
  2002   -1.95
  2003   -0.11
  2004    0.01
  2005   -0.04
  2006   -0.09
  2007   -0.21
  2008    1.14
  2009    0.48
  2010   -1.54
  2011    1.75
  2012    0.25
  2013    0.40
  2014   -0.83
  2015    0.47
  2016   -0.97
  2017    0.06
  2018   -0.22
  2019   -0.88
  2020    1.30
  2021   -0.76