What is the percentage of the popular vote when there were 90 seats available?
CREATE TABLE "election_results" (
  "year_of_election" real,
  "candidates_elected" real,
  "num_of_seats_available" real,
  "num_of_votes" text,
  "pct_of_popular_vote" text
);
SELECT "pct_of_popular_vote" FROM "election_results" WHERE "num_of_seats_available"=90;