what's the percentage of votes with election date being 1981
CREATE TABLE "parliamentary_elections" (
  "election_date" real,
  "party_leader" text,
  "number_of_votes_received" real,
  "percentage_of_votes" text,
  "number_of_deputies" real
);
SELECT "percentage_of_votes" FROM "parliamentary_elections" WHERE "election_date"=1981;