What is the average earnings of a United States player who had a score of 72-68-74-72=286?
CREATE TABLE "final_leaderboard" (
  "place" text,
  "player" text,
  "country" text,
  "score" text,
  "to_par" text,
  "earnings" real
);
SELECT AVG("earnings") FROM "final_leaderboard" WHERE "country"='united states' AND "score"='72-68-74-72=286';