Dates of birth
One of my good Ugandan friends is two years older than his birth certificate says. The law states that one must retire at the age of sixty but several years ago the government was so poor that there was no way it could afford to pay pensions. Obviously many people feared that when they reached retirement age they would have no way of paying for necessities. Therefore, as birth certificates in Uganda are not produced at the time of birth, it was possible to change your age when applying for it. By making yourself slightly younger than you really were, it meant that you would be able to work for a few years after you actually reach sixty.
Now pensions do exist, some people are making themselves older than they really are so that they can retire before they’re sixty!