What are the average wins that have great britain as the team?
CREATE TABLE "group_b" (
  "pos" real,
  "team" text,
  "wins" real,
  "ties" real,
  "losses" real,
  "goals" text,
  "diff" text,
  "points" text
);
SELECT AVG("wins") FROM "group_b" WHERE "team"='great britain';