What is the year of the winner from the army school, plays the halfback position, and has a % of points possible of 39.01%?
CREATE TABLE "winners" (
  "year" real,
  "winner" text,
  "school" text,
  "position" text,
  "points" text,
  "pct_of_points_possible" text
);
SELECT SUM("year") FROM "winners" WHERE "school"='army' AND "position"='halfback' AND "pct_of_points_possible"='39.01%';