What was the average number of points with bonus pts less than 31 with the rider dennis gavros?
CREATE TABLE "1966_season_finished_1st_54pts_out_of_19" (
  "rider" text,
  "matches" real,
  "rides" real,
  "bonus_pts" real,
  "total_points" real
);
SELECT AVG("total_points") FROM "1966_season_finished_1st_54pts_out_of_19" WHERE "rider"='dennis gavros' AND "bonus_pts"<31;