What sort of population numbers did modern-day east African states (such as Kenya, Tanzania, etc) have in the later Middle Ages?

by The_Manchurian

I can find vague numbers for modern-day European states in the Middle Ages, but I have no idea where to look for African states. Were the population numbers much lower, higher, or about the same? I'd like to know roughly exact numbers (to the nearest half million or whatever) but if no-one knows, a rough idea is fine. I don't know how accurate historians' knowledge of east African demographics before the modern period is.

The_Manchurian

As a secondary question, what kind of population numbers did the Swahili cities of this time (such as Zanzibar and Mombasa) have?