Trenberth and Hurrell North Pacific Index (NDJFM) 1899 -999.00 1900 1005.62 1901 1010.00 1902 1009.48 1903 1013.51 1904 1013.11 1905 1008.48 1906 1010.29 1907 1014.14 1908 1011.82 1909 1010.60 1910 1011.88 1911 1012.78 1912 1009.43 1913 1009.41 1914 1009.07 1915 1010.46 1916 1012.84 1917 1012.16 1918 1010.30 1919 1008.56 1920 1011.98 1921 1009.82 1922 1011.01 1923 1010.86 1924 1008.44 1925 1008.33 1926 1005.14 1927 1007.96 1928 1008.52 1929 1007.67 1930 1010.93 1931 1006.22 1932 1011.15 1933 1010.65 1934 1006.66 1935 1008.91 1936 1007.51 1937 1012.92 1938 1008.94 1939 1009.39 1940 1003.68 1941 1005.35 1942 1008.10 1943 1012.33 1944 1007.80 1945 1006.08 1946 1009.33 1947 1010.67 1948 1011.34 1949 1010.92 1950 1010.39 1951 1011.90 1952 1011.09 1953 1007.60 1954 1009.81 1955 1011.21 1956 1012.30 1957 1010.31 1958 1007.83 1959 1010.30 1960 1009.26 1961 1006.87 1962 1010.68 1963 1007.47 1964 1009.08 1965 1009.89 1966 1011.27 1967 1010.96 1968 1009.02 1969 1010.83 1970 1005.74 1971 1011.48 1972 1011.84 1973 1009.51 1974 1009.06 1975 1010.02 1976 1010.09 1977 1005.95 1978 1006.49 1979 1010.55 1980 1007.69 1981 1004.44 1982 1010.60 1983 1003.46 1984 1006.28 1985 1010.01 1986 1004.79 1987 1005.97 1988 1008.13 1989 1011.74 1990 1010.90 1991 1011.24 1992 1006.45 1993 1008.75 1994 1010.36 1995 1008.56 1996 1007.77 1997 1008.67 1998 1005.48 1999 1009.45 2000 1008.45 2001 1007.08 2002 1009.20 2003 1005.06 2004 1008.56 2005 1008.15 2006 1010.11 2007 1009.83 2008 1009.30 2009 1013.47 2010 1006.49 2011 1011.13 2012 1010.33 2013 1010.31 2014 1009.81 2015 1007.86 2016 1006.59 2017 1010.26 2018 1012.98 2019 1009.40 2020 1011.76 2021 1010.64 2022 1010.52 2023 1011.92