what's the number of households with per capita income being $16,820
CREATE TABLE "nevada_places_ranked_by_per_capita_incom" (
  "rank" real,
  "place" text,
  "county" text,
  "per_capita_income" text,
  "median_house_hold_income" text,
  "population" real,
  "number_of_households" real
);
SELECT "number_of_households" FROM "nevada_places_ranked_by_per_capita_incom" WHERE "per_capita_income"='$16,820';