10 0 RESERVED 21 1 MANUAL READING FROM VERTICAL TIDE STAFF 32 2 MANUAL READING FROM SINGLE AUTOMATIC RECORDER AT STATION 43 3 MANUAL READING FROM MULTIPLE AUTOMATIC RECORDERS AT STATION 54 4 AUTOMATIC READING FROM SINGLE AUTOMATIC RECORDER AT STATION WITHOUT LEVEL REFERENCE CHECK 65 5 AUTOMATIC READING FROM SINGLE AUTOMATIC RECORDER AT STATION WITH LEVEL REFERENCE CHECK, OR FROM MULTIPLE AUTOMATIC RECORDERS 76 6 RESERVED 87 7 MISSING VALUE 9