An instance of reverse heaping of ages

This note reports on an interesting example of reverse heaping of ages for data from the Saudi Arabian social insurance system. Peaks occur for the number of workers at ages corresponding to years of birth ending in zeroes and fives, while there are troughs at such ages for the average monthly wages. Such troughs almost certainly are the result of workers with less education using a rounded year of birth, and, correspondingly, such workers would tend to have lower earnings.