SQL dividing the sum of two results on a select

Could anybody tell me why (SUM(TSCOMD)/SUM(TSSLS$)) always returns 0 in the 
following select statement:

V5R2,
The two SUM() fields never equal 0 yet the result of the division comes back as 
0?????????

SELECT                        
              TSSLS#,
               IDGRP,
              SUM(TSSLS$),               
              SUM(TSCOMD),
              (SUM(TSCOMD)/SUM(TSSLS$))
 FROM LIB.SLPTS
 JOIN LIB.INDESCRP  ON IDS# = TSPRD and IDSF = 'A' 
 WHERE IDGRP = 957 AND   TSSTS <> 'D'
GROUP BY IDGRP, TSSLS#
ORDER BY IDGRP, TSSLS#