What was the ranking of the season finale aired on May 8, 2006? 
CREATE TABLE "u_s_television_ratings" (
  "season" text,
  "network" text,
  "season_premiere" text,
  "season_finale" text,
  "tv_season" text,
  "ranking" text,
  "viewers_in_millions" text
);
SELECT "ranking" FROM "u_s_television_ratings" WHERE "season_finale"='May 8, 2006';