I never realized how often we use isotypes/pictographs, so I went looking for an older examples. The pictures I posted is from 1944, and is comparing the 1937 male to female ratio in Great Britian and in the Soviet Union. There are five age groups, and each symbol equals 250,00 people.
Of course this isn't the earliest example of pictographs. Pictographs can be dated clear back to the days of cave painting, but Otto Neurath is the one credited for making them universal. The person symbol is still used to this day, and variations of it can ben seen quite often. The universal sign for restrooms is a great example. The only variation is the dress shape on the female sign. In the picture above, the shape of the person according to country. People aren't the only thing used in pictographs. They are now used in parks, airports, office buildings, malls, etc, and the simpler the better. I honestly don't see pictographs going away anytime soon. They may actually gain even more popularity.
sources: fulltable.com/iso/images01/16.jpg; aiga.com