Which Laps has a Year of 2007?
CREATE TABLE "24_hours_of_le_mans_results" (
  "year" real,
  "team" text,
  "co_drivers" text,
  "class" text,
  "laps" real,
  "pos" text,
  "class_pos" text
);
SELECT AVG("laps") FROM "24_hours_of_le_mans_results" WHERE "year"=2007;