High level worker number cycling.

My high level worker numbers increase a lot one month then gradually decline over several game months to zero, then increase again. I have not built corps for several game years. What can I do to have the number of high level workers increase incrementally with no real decrease the following months without having to buy population?
My education index is 170
My health is 190

What country and world?

good question.
I would like to see it too.

country name and world.

Stannislovokia on white giant
It takes approx. 5 to 6 months to cycle down to 0 after reaching a high of about 60k.

I just looked into it.

The market for workers is always on the move.
people leave corporations, go to other corporations, fired and become unemployed etc.

It is less so if corporations are short of workers but in your country all corporations have all the workers they need.

so workers and professionals are moving trying to find jobs.

high level workers try to find a job as mid level or low level workers.
When their numbers go very low, or even zero, they move back in large numbers as they assume there are jobs.

Check the numbers in the other workers groups, these fluctuate too.

Is there anything I can do to encourage an increase in the number of high level workers? What can I do to make the number more stable?