When was the pre-season game record achieved?
CREATE TABLE "table1_21436373_10" (
  "type_of_record" text,
  "attendance" real,
  "date_year" text,
  "stadium" text,
  "result_games" text
);
SELECT "date_year" FROM "table1_21436373_10" WHERE "type_of_record"='Pre-season game';