How many 7th season episodes had 2nd season viewerships of 6 594 469?
CREATE TABLE "viewing_figures" (
  "episode" real,
  "1st_season" text,
  "2nd_season" text,
  "3rd_season" text,
  "4th_season" text,
  "5th_season" text,
  "6th_season" text,
  "7th_season" text
);
SELECT COUNT("7th_season") FROM "viewing_figures" WHERE "2nd_season"='6 594 469';