Rank / Crew Proportions

[Joe's #2 son]

When you play a career, I realized everyone will be promoted way beyond what a real crew would be. I used different dice methods to rotate crew, but what I would really like to know is how many of a specific rank would have been aboard a typical uboat. This would help to know who gets the dice throw according to rank. I'm sure some of you that have had naval service experience could probably give a good ratio estimate of a crew. Again, thanks to this community.