What is the average # Of National Votes, when the Election is before 1992, when the % Of Prefectural Vote is 39.5%, when Leader is Takeo Fukuda, and when # Of Seats Won is greater than 63?
CREATE TABLE "councillors_election_results" (
  "election" real,
  "leader" text,
  "num_of_seats_won" real,
  "num_of_national_votes" real,
  "pct_of_national_vote" text,
  "num_of_prefectural_votes" real,
  "pct_of_prefectural_vote" text
);
SELECT AVG("num_of_national_votes") FROM "councillors_election_results" WHERE "election"<1992 AND "pct_of_prefectural_vote"='39.5%' AND "leader"='takeo fukuda' AND "num_of_seats_won">63;