Taking a look at the systems broken down by Allegiance: 

- white circles represent >= TL15 and yellow circles represent population >= 5*10^10 - it appeared that there is no Zhodani TL15 world, and there's not, at least in the official data. Has that always been that way? Is it intentional? 

Also, if you look at the power of an empire as a combination of population and tech level, it seems like the third imperium should be far more powerful than anyone else.