srecord Percent(double percent) {
  void set(double percent) { percent = percent; }
  double get() { ret percent; }
  
  toString {
    ret percent + " %";
  }
  
  S renderWithDecimals(int decimals) {
    ret formatDouble(percent, decimals) + " %";
  }
  
  static Percent ratio(double x, double y) {
    ret new Percent(doubleRatio(x, y)*100);
  }
}