Region population:
German Federation:
Region 1 (4500)495+; Region 2 (4500)495+
New New York:
Region 1 (4500)495+; Region 2 (4500)495+
S.U.D.Z
Region 1 (4500)450+; Region 2 (4500)495+
The Peacekeepers
Region 1 (4500)450+; Region 2 (4500)450+
New Persia
Region 1 (4500)495+; Region 2 (4500)495+
MartinLuther's nation
Region 1 (4500)450+; Region 2 (4500)450+
This is how the population is calculated: The population every turn grows by a 10%. If your region is in a water-connected area, the growth will increase by 1%. I just realized that the geographical map was down for some reason in the OP, so I'll put it here.
The infertile areas on the map give a -3.5% penalty of growth. Rivers give a bonus of 1.5%. Since the map was down, the penalty has been removed only for this turn. Feel free to move if your zone falls in the penalty zone. Don't worry, if you move, you still have 5 claims to use. Also remember to not spread too much in water-zone areas so all your regions have the 1% bonus, you'll still suffer from the stability penalty.