How figure out actual city size

[Radar]

This has been bugging me for a while, but I would like to know the actual size of my cities. The number 60 doesn't mean much to me except for that it is big. I have tried taking the civ population divided by the total number of population units for all of my cites, but that number makes no sense. It is to big. Please help me figure this out.

[Yazeran]

I think the answer is that when you shift from one age to another the multiplication facter of the actual number of people within a city changes. I'm not fluent in the txt-files, but i do believe the answer is there. As far as i recall (can't remember where i read it - sorry) the city-size depends on number of citicen multiplied by a number depending on civ age (eg aincient:1, modern:?)
Hope this helps..