In my short experience it seems to be pretty random - I once had two stakes come in within a few minutes of each other, most times it takes 2-3 days to get a stake. The total amount of the stake should still amount to the equivalent of 5% per month whenever you actually get it.
So the amount earned will be shown in "stake" field, or in my total number of coins?
First in "stake" and after confirmation in total number.