The entire empire is a premium member empire.
check the birth rates percentages and you will see that they are very high.
compare to a C3 country or any other non premium country.
the age groups are really not according to the normal age distribution.
check the percetanges per age group and compare to a C3 country.
But I could see that birth numbers are increasing and the population in the young groups is increasing.
this will extend, in time to older age groups.
give it 20 years (40 days) and it will show very high growth number.
By then, the population numbers will become much higher up to the age of maybe 30, and birth numbers will be based on the population numbers in these groups.
If no transfers have taken place, I have no clue why the age groups are in such a disarray.