[it's been a long time] a question on voter percentages

it’s been a long time since i’ve been around here and since i’ve had the time to work on the electricity mod.
in the moment i’m messing around with stuck’s demography mod, trying to further integrate it into the game to be hopefully
able to simulate energy demand from it in the end.
so i found a new way to simulate the adults, basically i assume,

youth+adults+retired=100% since youth and retired are provided by the game as youth_perc and retired_perc,

[100-(youth_perc)]-(retired_perc) would be all adults in society.
this works pretty fine, but since becoming adult means you are not a part of the states youth anymore (same with adult becoming retirees),
i tried to have the adult simulation influence the youth_perc and retired_perc. i’m able to start a game, but as soon as i click next, the game crashes, so it’s obviously not possible to have an influence on this value.
so, anyone got an idea how to get this working?