How many households have a median family income of $60,400?
CREATE TABLE "virginia_counties_and_cities_ranked_by_p" (
  "county_or_city" text,
  "per_capita_income" text,
  "median_household_income" text,
  "median_family_income" text,
  "population" real,
  "number_of_households" real
);
SELECT "number_of_households" FROM "virginia_counties_and_cities_ranked_by_p" WHERE "median_family_income"='$60,400';