date value date elev 1949-06-01 1397.0 1993-11-01 1395.60 1955-06-25 1394.0 1994-02-16 1395.78 1956-06-08 1395.7 1994-05-09 1397.38 1956-09-24 1395.2 1994-07-26 1398.52 1957-04-29 1395.3 1994-10-13 1397.72 1957-10-04 1394.6 1995-01-23 1397.96 1958-06-23 1394.4 1995-05-10 1401.41 1958-10-03 1395.0 1995-07-24 1401.28 1959-10-10 1394.6 1995-10-16 1400.86 1960-05-06 1395.59 1996-02-20 1401.22 1960-06-17 1395.71 1996-05-09 1403.64 1960-09-30 1394.58 1996-07-22 1403.80 1964-05-19 1394.99 1996-10-15 1403.11 1964-10-02 1396.20 1997-02-10 1403.35 1965-05-20 1396.99 1997-05-12 1406.57 1965-10-02 1397.10 1997-07-28 1406.77 1966-05-24 1398.82 -- -- 1966-06-22 1398.50 -- -- 1966-08-11 1398.24 -- -- 1966-10-13 1397.62 -- -- 1967-05-15 1399.56 -- -- 1967-10-26 1398.13 -- -- 1968-05-17 1398.80 -- -- 1968-10-24 1397.73 -- -- 1969-05-21 1399.36 -- -- 1969-10-08 1398.49 -- -- 1970-05-19 1399.19 -- -- 1970-10-05 1398.15 -- -- 1971-05-19 1399.67 -- -- 1971-08-19 1399.25 -- -- 1971-11-18 1399.16 -- -- 1972-05-17 1399.90 -- -- 1972-08-15 1398.99 -- -- 1972-11-15 1398.49 -- -- 1973-02-07 1398.51 -- -- 1973-05-17 1398.41 -- -- 1973-08-15 1397.53 -- -- 1973-11-15 1397.62 -- -- 1974-02-14 1397.72 -- -- 1974-05-23 1400.20 -- -- 1974-08-29 1400.10 -- -- 1974-12-12 1399.30 -- -- 1975-06-18 1399.95 -- -- 1975-10-21 1398.90 -- -- 1976-01-20 1398.82 -- -- 1976-05-04 1399.35 -- -- 1976-07-22 1398.54 -- -- 1977-10-17 1397.28 -- -- 1978-01-17 1396.23 -- -- 1978-05-09 1397.45 -- -- 1978-08-17 1396.61 -- -- 1978-10-17 1396.55 -- -- 1979-05-16 1399.24 -- -- 1979-08-08 1398.37 -- --