static <A> S renderRepetitionPercentage(Cl<A> entries) {
  if (empty(entries)) ret "no data";
  int total = l(entries), unique = countUniques(entries);
  int repeated = total-unique;
  ret "Repetition: " + formatDouble(doublePercentRatio(repeated, total), 1) + " %"
    + spaceRoundBracket(joinWithComma(
      n2(total, "total entry", "total entries"),
      n2(unique, "repeated entry", "repeated entries")));
}