What is the rank of the company known for retailing?
CREATE TABLE "public_companies" (
  "state_rank_by_revenue" real,
  "company_name" text,
  "national_rank" real,
  "revenue_billions_2012_estimate" text,
  "headquarters_city" text,
  "known_for" text
);
SELECT COUNT("state_rank_by_revenue") FROM "public_companies" WHERE "known_for"='Retailing';