What is the poverty rate in the county that has a market income per capita of $16,420?
CREATE TABLE "list_of_appalachian_regional_commission_" (
  "county" text,
  "population" real,
  "unemployment_rate" text,
  "market_income_per_capita" text,
  "poverty_rate" text,
  "status" text
);
SELECT "poverty_rate" FROM "list_of_appalachian_regional_commission_" WHERE "market_income_per_capita"='$16,420';