Top one lists those populations (in millions) from most populous to least populous. Bottom one shows exactly how many millions for each world, the alliance or kingdom each world belongs to, and the total number of worlds and total number of 'Mech battalions possessed by that alliance or kingdom.
Highly populous worlds are relatively rare, just like in the Inner Sphere, and only appear only in the largest, most stable nations; curiously, the size of those populations seem to be in tune with the overall size of the nation. Something like
[Total Population in millions] = 5*[regiments^(20/7)]with 60%-70% of that total being concentrated on the capital world. (This approximation seems okay for the big three states, and Randis too, but is a little off for Novo Franklin and the Lothian League. A proper logistic function might get better results.)
I suspect the Outworld and Independent worlds are most representative of the Periphery in general (and perhaps the Inner Sphere too), though the kink in the top chart from world #32 to world #33 (Oberon to Lushann) makes it look like populations smaller than 40,000 are underrepresented.
Bandit Kingdoms have the lowest populations. Not surprising, since they tend to be described as having the worst infrastructure. Could also represent how few people a unit of 'Mechs can actually conquer and control.