what is the year where the qualifying score was 15.150?
CREATE TABLE "2008_season" (
  "year" real,
  "competition" text,
  "location" text,
  "event" text,
  "final_rank" text,
  "final_score" text,
  "qualifying_rank" real,
  "qualifying_score" text
);
SELECT "year" FROM "2008_season" WHERE "qualifying_score"='15.150';