Where did he finish when he started at 21.6?
CREATE TABLE "career_nascar_statistics" (
  "year" real,
  "races" real,
  "wins" real,
  "poles" real,
  "top_5" real,
  "top_10" real,
  "dnf" real,
  "finish" text,
  "start" text,
  "winnings" text,
  "season_rank" text,
  "team_s" text
);
SELECT COUNT("finish") FROM "career_nascar_statistics" WHERE "start"='21.6';