Hurrell PC-Based North Atlantic Oscillation Index (JJA)
  1899    0.20
  1900   -0.66
  1901    1.04
  1902   -2.18
  1903   -2.12
  1904   -1.06
  1905   -0.05
  1906   -0.69
  1907   -1.94
  1908   -0.04
  1909   -0.16
  1910   -1.70
  1911   -0.53
  1912   -1.43
  1913    0.74
  1914    0.36
  1915   -1.56
  1916   -0.38
  1917   -0.48
  1918   -0.57
  1919    1.01
  1920    0.89
  1921    0.20
  1922    0.59
  1923   -0.19
  1924   -0.09
  1925    0.57
  1926   -0.32
  1927   -0.37
  1928   -1.00
  1929   -0.59
  1930   -0.52
  1931   -0.93
  1932   -0.03
  1933    1.02
  1934   -0.41
  1935    0.69
  1936    0.44
  1937    1.31
  1938    1.09
  1939   -0.02
  1940    0.63
  1941    0.72
  1942    0.28
  1943   -1.37
  1944   -0.14
  1945   -0.43
  1946    0.92
  1947    1.06
  1948   -0.71
  1949    0.15
  1950   -0.33
  1951   -0.19
  1952    0.37
  1953    0.73
  1954   -0.29
  1955    1.81
  1956   -0.81
  1957   -0.69
  1958   -2.34
  1959    0.44
  1960   -0.84
  1961    1.43
  1962   -0.59
  1963   -0.74
  1964    0.60
  1965    0.01
  1966    0.11
  1967    1.66
  1968   -0.06
  1969    0.40
  1970    1.14
  1971    0.05
  1972    1.30
  1973    1.07
  1974   -0.17
  1975    0.93
  1976    1.48
  1977   -0.64
  1978    0.17
  1979    1.07
  1980   -0.93
  1981    0.88
  1982   -0.15
  1983    2.11
  1984    1.07
  1985   -0.47
  1986    0.39
  1987   -1.06
  1988    0.69
  1989    1.58
  1990    0.67
  1991    0.72
  1992    0.27
  1993   -1.14
  1994    2.05
  1995    0.74
  1996    1.28
  1997    0.05
  1998   -0.67
  1999    0.95
  2000   -0.05
  2001   -0.04
  2002    0.80
  2003   -0.30
  2004   -0.30
  2005    0.56
  2006    1.10
  2007   -1.11
  2008   -1.32
  2009   -2.05
  2010   -0.43
  2011   -2.09
  2012   -1.57
  2013    1.68
  2014   -0.86
  2015   -1.63
  2016   -0.69
  2017    0.36
  2018    1.89
  2019   -2.10
  2020   -0.29
  2021    1.10