Population increase and decrease

[dragoon500ly]

Here's a question...

In TM 1-1 the population die off is listed as 95% following the nuclear strikes. Ok, seems a reasonable percentage with the strikes and the resulting disruption that a TEOTWAWKI scenario.

So the question is, has anybody sat down and figured out a reasonable birthrate for the aftermath? Some of the online sources have a percentage as high as 50% for a sustainable birthrate, which seems to be very unlikely. I've tried plugging various historical birthrates and can't find one that seems logical based on a total disruption of society.

So any help is greatly appreciated!