How many values are in the PF cell when Jennifer Jones is skip?
CREATE TABLE "standings" (
  "province" text,
  "skip" text,
  "w" real,
  "l" real,
  "pf" real,
  "pa" real,
  "ends_won" real,
  "ends_lost" real,
  "blank_ends" real,
  "stolen_ends" real,
  "shot_pct" real
);
SELECT COUNT("pf") FROM "standings" WHERE "skip"='Jennifer Jones';