Trenberth and Hurrell North Pacific Index Anomalies (NDJFM)
  1899   -999.
  1900   -3.28
  1901    1.10
  1902    0.58
  1903    4.61
  1904    4.21
  1905   -0.42
  1906    1.39
  1907    5.24
  1908    2.92
  1909    1.70
  1910    2.98
  1911    3.88
  1912    0.53
  1913    0.51
  1914    0.17
  1915    1.56
  1916    3.94
  1917    3.26
  1918    1.40
  1919   -0.34
  1920    3.08
  1921    0.92
  1922    2.11
  1923    1.96
  1924   -0.46
  1925   -0.57
  1926   -3.76
  1927   -0.94
  1928   -0.38
  1929   -1.23
  1930    2.03
  1931   -2.68
  1932    2.25
  1933    1.75
  1934   -2.24
  1935    0.01
  1936   -1.39
  1937    4.02
  1938    0.04
  1939    0.49
  1940   -5.22
  1941   -3.55
  1942   -0.80
  1943    3.43
  1944   -1.10
  1945   -2.82
  1946    0.43
  1947    1.77
  1948    2.44
  1949    2.02
  1950    1.49
  1951    3.00
  1952    2.19
  1953   -1.30
  1954    0.91
  1955    2.31
  1956    3.40
  1957    1.41
  1958   -1.07
  1959    1.40
  1960    0.36
  1961   -2.03
  1962    1.78
  1963   -1.43
  1964    0.18
  1965    0.99
  1966    2.37
  1967    2.06
  1968    0.12
  1969    1.93
  1970   -3.16
  1971    2.58
  1972    2.94
  1973    0.61
  1974    0.16
  1975    1.12
  1976    1.19
  1977   -2.95
  1978   -2.41
  1979    1.65
  1980   -1.21
  1981   -4.46
  1982    1.70
  1983   -5.44
  1984   -2.62
  1985    1.11
  1986   -4.11
  1987   -2.93
  1988   -0.77
  1989    2.84
  1990    2.00
  1991    2.34
  1992   -2.45
  1993   -0.15
  1994    1.46
  1995   -0.34
  1996   -1.13
  1997   -0.23
  1998   -3.42
  1999    0.55
  2000   -0.45
  2001   -1.82
  2002    0.30
  2003   -3.84
  2004   -0.34
  2005   -0.75
  2006    1.21
  2007    0.93
  2008    0.40
  2009    4.57
  2010   -2.41
  2011    2.23
  2012    1.43
  2013    1.41
  2014    0.91
  2015   -1.04
  2016   -2.31
  2017    1.36
  2018    4.08
  2019    0.50
  2020    2.86
  2021    1.74
  2022    1.62