What Number of households have a Median family income of $58,491?
CREATE TABLE "minnesota_counties_ranked_by_per_capita_" (
  "county" text,
  "per_capita_income" text,
  "median_household_income" text,
  "median_family_income" text,
  "population" real,
  "number_of_households" real
);
SELECT "number_of_households" FROM "minnesota_counties_ranked_by_per_capita_" WHERE "median_family_income"='$58,491';