What is the average overall of Ken Whisenhunt, who has a pick # of 5?
CREATE TABLE "atlanta_falcons_draft_history" (
  "round" real,
  "pick_num" real,
  "overall" real,
  "name" text,
  "position" text,
  "college" text
);
SELECT AVG("overall") FROM "atlanta_falcons_draft_history" WHERE "pick_num"=5 AND "name"='ken whisenhunt';