What is the number of final position-tours Mariano Piccoli, who has more than 20 final position-giros, before 1999 has?
CREATE TABLE "grand_tour_finishers" (
  "rider" text,
  "year" real,
  "final_position_giro" real,
  "final_position_tour" real,
  "final_position_vuelta" real
);
SELECT COUNT("final_position_tour") FROM "grand_tour_finishers" WHERE "final_position_giro">20 AND "rider"='mariano piccoli' AND "year"<1999;