From descr_mercenaries.txt:
Code:
pool North_Africa
regions Mauretania Numidia Gaetulia Sahara
unit merc libyan infantry, exp 0 cost 350 replenish 0.1 - 0.15 max 2 initial 1
unit merc numidian cavalry, exp 1 cost 750 replenish 0.1 - 0.15 max 2 initial 1
unit merc balearic slingers, exp 0 cost 750 replenish 0.03 - 0.05 max 1 initial 0
unit merc elephants, exp 0 cost 4000 replenish 0.005 - 0.015 max 1 initial 0
The campaign starts out with 0 elephant mercenaries available in North Africa. These units will be generated at a rate that is somewhere between 0.005 and 0.015. I assume that it means a probability that is checked each turn. So at worst, one elephant will appear (on average) once per 200 turns, at best you can get one per 67 turns.
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