The Dow Jones average of 30 industrials dropped 16.54 to 2,106.15, bringing its loss for the week to 25.43 points. Declining issues outnumbered advances by more than 3 to 2 on the New York Stock Exchange, with 551 up, 854 down and 530 unchanged. Big Board volume totaled 136.07 million shares, against 156.10 million in the previous session. The NYSE's composite index fell .81 to 152.81.