year PDO 12-yr low-pass filtered PDO 1854 0.57007 -999.0 1855 0.69606 -999.0 1856 -0.12479 -999.0 1857 0.27116 -999.0 1858 0.32812 -999.0 1859 -1.81737 -999.0 1860 -0.38826 -0.26414 1861 -0.24309 -0.16253 1862 0.38070 -0.02192 1863 0.42225 0.10337 1864 0.11483 0.18993 1865 0.52657 0.25249 1866 -0.34981 0.31947 1867 0.32302 0.39998 1868 0.41761 0.46873 1869 1.72950 0.48544 1870 0.23459 0.42564 1871 0.22879 0.29951 1872 0.14045 0.14661 1873 -0.47186 0.01698 1874 0.20441 -0.04966 1875 -0.08853 -0.04064 1876 -1.04586 0.02391 1877 0.23899 0.09640 1878 1.71834 0.12616 1879 0.26846 0.09354 1880 -1.34991 0.03050 1881 0.73300 0.00073 1882 -0.80920 0.05209 1883 -0.20834 0.18207 1884 0.27411 0.33813 1885 2.19464 0.45643 1886 0.50521 0.49940 1887 -0.86132 0.46306 1888 0.87463 0.35432 1889 1.40724 0.16847 1890 -0.74675 -0.09765 1891 0.29978 -0.41797 1892 -1.09279 -0.72370 1893 -1.38477 -0.92529 1894 -2.72273 -0.96039 1895 -0.34577 -0.82809 1896 -0.37406 -0.58723 1897 0.04309 -0.31815 1898 -0.21366 -0.08524 1899 -0.21515 0.08341 1900 1.52203 0.19638 1901 -0.57010 0.28218 1902 0.35705 0.36806 1903 0.11406 0.45669 1904 0.69112 0.52035 1905 1.35596 0.51449 1906 1.01855 0.40715 1907 -0.40152 0.20678 1908 0.11809 -0.03309 1909 0.08537 -0.23234 1910 -1.68772 -0.31853 1911 -0.63966 -0.26292 1912 0.11564 -0.10266 1913 -0.20873 0.07023 1914 1.08235 0.15376 1915 1.54268 0.09216 1916 -0.32535 -0.09522 1917 -1.57486 -0.33335 1918 -0.56173 -0.54263 1919 -0.63257 -0.68094 1920 -0.41912 -0.74280 1921 -1.01533 -0.73310 1922 -1.51833 -0.64795 1923 -0.07850 -0.48109 1924 -0.49883 -0.24788 1925 -0.77925 0.00971 1926 1.89275 0.23946 1927 0.16344 0.40367 1928 0.70946 0.49282 1929 -0.01548 0.51406 1930 0.56860 0.48229 1931 1.64155 0.41946 1932 0.11126 0.35408 1933 -1.36994 0.31401 1934 1.05885 0.30754 1935 0.27333 0.32539 1936 1.28350 0.36394 1937 -0.14299 0.44058 1938 -0.17564 0.57826 1939 -0.34754 0.76112 1940 2.21269 0.91454 1941 2.44895 0.94228 1942 1.22376 0.79642 1943 0.28586 0.51486 1944 -0.75794 0.18744 1945 -0.40257 -0.11396 1946 -0.19239 -0.37672 1947 0.39743 -0.62718 1948 -1.12354 -0.87855 1949 -1.61625 -1.10265 1950 -2.00145 -1.25175 1951 -1.20290 -1.30133 1952 -1.55428 -1.26667 1953 -0.86541 -1.17891 1954 -0.56563 -1.05035 1955 -1.51140 -0.86652 1956 -1.78915 -0.61593 1957 -0.10941 -0.32686 1958 1.13975 -0.07144 1959 0.40350 0.07169 1960 0.40255 0.06719 1961 0.17446 -0.05838 1962 -0.83355 -0.23567 1963 -0.16316 -0.39391 1964 -1.28572 -0.49329 1965 -0.21421 -0.53049 1966 -0.40516 -0.53014 1967 -0.85336 -0.52633 1968 -0.11405 -0.54895 1969 -0.71397 -0.61317 1970 0.08229 -0.71371 1971 -1.62139 -0.82993 1972 -1.15190 -0.92974 1973 -0.77756 -0.97664 1974 -0.83063 -0.93487 1975 -1.64881 -0.77819 1976 -1.30371 -0.50830 1977 0.09376 -0.16362 1978 1.13996 0.19082 1979 0.16488 0.49006 1980 1.18611 0.69677 1981 1.26002 0.80869 1982 -0.09915 0.85009 1983 1.92388 0.85276 1984 0.86493 0.83670 1985 -0.35799 0.80303 1986 1.38931 0.73684 1987 1.54379 0.62744 1988 0.41470 0.49294 1989 -0.35260 0.38481 1990 0.14266 0.36233 1991 -0.75035 0.45249 1992 1.39726 0.63114 1993 1.36529 0.83267 1994 0.78309 0.97915 1995 1.19732 1.00626 1996 1.45371 0.87799 1997 1.35015 0.60272 1998 0.93086 0.24260 1999 -1.76741 -0.09576 2000 -0.73103 -0.30338 2001 -0.89845 -0.32796 2002 -0.63741 -0.20378 2003 0.74182 -0.03767 2004 0.45300 0.05086 2005 1.02414 -0.00434 2006 -0.37271 -0.18923 2007 -0.39750 -0.42799 2008 -1.59468 -0.63415 2009 -1.42869 -0.74773 2010 0.32989 -0.74067 2011 -1.07447 -0.60324 2012 -1.32781 -0.33850 2013 -0.66759 -999.0 2014 1.04953 -999.0 2015 1.56851 -999.0 2016 2.07226 -999.0 2017 0.49199 -999.0 2018 -0.07078 -999.0