CREATE TABLE "rating_figures" (
  "episode" real,
  "date" text,
  "official_rating_4" text,
  "share_4" text,
  "official_rating_16_39" text,
  "share_16_39" text
);

Question: When did the official rating 4+ reach 4 633 925?
SQL: SELECT "date" FROM "rating_figures" WHERE "official_rating_4"='4 633 925';