The populations are roughly known. In the roman empire, I think the numbers were something around 1:2:2 for citizens, regulars, and slaves. It's also difficult

The populations are roughly known. In the roman empire, I think the numbers were something around 1:2:2 for citizens, regulars, and slaves. It's also difficult to measure wealth. Should we use gold? Rate of technological advancement would probably be the best measure. There are a fair number of records from ancient times, with huge holes.