Name the viewers for production code for 3x6704
CREATE TABLE "table1_22347090_5" (
  "no_in_series" real,
  "no_in_season" real,
  "title" text,
  "directed_by" text,
  "written_by" text,
  "original_air_date" text,
  "production_code" text,
  "u_s_viewers_million" text
);
SELECT "u_s_viewers_million" FROM "table1_22347090_5" WHERE "production_code"='3X6704';