Name the dates for margin of victory being 5 strokes
CREATE TABLE "winners" (
  "year" real,
  "dates" text,
  "champion" text,
  "country" text,
  "score" real,
  "to_par" text,
  "margin_of_victory" text,
  "tournament_location" text,
  "purse_us" real,
  "winners_share" text
);
SELECT COUNT("dates") FROM "winners" WHERE "margin_of_victory"='5 strokes';