How much is the total ERP W for an 107.9 fm freqeuncy MHz?
CREATE TABLE "translators" (
  "call_sign" text,
  "frequency_m_hz" text,
  "city_of_license" text,
  "erp_w" real,
  "class" text,
  "fcc_info" text
);
SELECT COUNT("erp_w") FROM "translators" WHERE "frequency_m_hz"='107.9 fm';