what is the number of weekly rank where the total is 1980000?
CREATE TABLE "ratings" (
  "episode_number_production_number" text,
  "title" text,
  "sydney" real,
  "melbourne" real,
  "brisbane" real,
  "adelaide" real,
  "perth" real,
  "total" real,
  "weekly_rank" text,
  "nightly_rank" text
);
SELECT COUNT("weekly_rank") FROM "ratings" WHERE "total"=1980000;