How many millions of total viewers watched season #8?
CREATE TABLE "table1_12419515_4" (
  "series_num" real,
  "season_num" real,
  "title" text,
  "directed_by" text,
  "written_by" text,
  "original_air_date" text,
  "total_viewers_in_millions" text
);
SELECT "total_viewers_in_millions" FROM "table1_12419515_4" WHERE "season_num"=8;