What is the frequency for the city of Lamar, Colorado?
CREATE TABLE "translators" (
  "call_sign" text,
  "frequency_m_hz" real,
  "city_of_license" text,
  "erp_w" real,
  "class" text,
  "fcc_info" text
);
SELECT AVG("frequency_m_hz") FROM "translators" WHERE "city_of_license"='lamar, colorado';