What was Attendance/G with Tms more than 18?
CREATE TABLE "record_as_j_league_member" (
  "season" real,
  "div" text,
  "tms" real,
  "pos" real,
  "attendance_g" real,
  "emperor_s_cup" text
);
SELECT AVG("attendance_g") FROM "record_as_j_league_member" WHERE "tms">18;