Why the average misleads

A drop with a fixed rate has no memory: each kill has the same chance, however long you have farmed. That makes the spread wide. At a rate of one per hundred kills, half of players have it by kill 69, but one player in ten is still waiting at kill 230.

Kinah Ledger doesn't print the game files' drop rates, because they don't match what players see. Measured rates fill in as players submit sessions with the tracker.