How many networks aired the franchise in 1981 only?
CREATE TABLE "all_in_the_family_till_death_us_do_part" (
  "region_country" text,
  "local_name" text,
  "network" text,
  "dates_aired" text,
  "starring" text
);
SELECT COUNT("network") FROM "all_in_the_family_till_death_us_do_part" WHERE "dates_aired"='1981';