CREATE TABLE table_39545 ("Rank" FLOAT, "Place" TEXT, "County" TEXT, "Per Capita Income" TEXT, "Median House- hold Income" TEXT, "Median Family Income" TEXT, "Population" FLOAT, "Number of Households" FLOAT)

What County has a Median Family Income of $79,331?
SELECT "County" FROM table_39545 WHERE "Median Family Income" = '$79,331'
SELECT "County" FROM "table_39545" WHERE "Median Family Income" = '$79,331'