StatsIterator - what is the significance of 23?

[David Medinets]

At the risk of having overlooked something obvious, I was curious about the
occurrence of 23 in the StatsIterator code:

  public void next() throws IOException {
    super.next();
    numRead++;

    if (numRead % 23 == 0) {
      readCounter.addAndGet(numRead);
      numRead = 0;
    }
  }

I'm also wondering about the StatsIterator in general. The member variables
are all private. They are incremented but never used.