A History of the Population and Rate of Urbanization of the Medieval Roman Empire

[B-29_Bomber]

I was playing a game of EUIV: M&T 2.0 as the Romans and I've restored the Eastern frontier to its height in the early 11th Century (or at least as close as you can in M&T). Indeed, the only stuff I don't control on this map:

Are the Ionian Islands, Croatia, Italy, and Cyprus. I currently rule over 12.94 million people with an urbanization rate of 16.35% and I was wondering how I was doing from a historical perspective in this regard.