SIGNAL ON ERROR
F='AVERAGE.TMP'
DO I=1
   L=READ(F)
   IF EOF(F) THEN LEAVE
   X=0
   WL=WORDS(L)
   IF WL>0 THEN DO
      DO O=1 TO WL
         WO=WORD(L,O)
         IF ^DATATYPE(WO,'N') THEN DO
            TRACE ?R
            NOP
         END
         X=X+WO
      END
      AV.I=X/WL
   END
   ELSE AV.I=''
END
NU=I-1

O=OPEN(F,'W')
DO I=1 TO NU
   CALL WRITE O,AV.I,nl
END
CALL CLOSE O
EXIT

ERROR:
NOP
EXIT