private Hashtable getLabelTable(int min, int max, int inc) {
    Hashtable<Integer,JLabel> table = new Hashtable<Integer,JLabel>();
    for (int j = min; j <= max; j += inc) {
      String s = String.format("%.2f", (j+4)/20.0);
      table.put(Integer.valueOf(j), new JLabel(s));
    }
    return table;
  }