Here's my counts so far. Still not done yet, but I'll update it once I'm finished with all the dungeon portions
EDIT: Finally got all the dungeons done. Here's my final results
Code:
Instance Run Total for Drop
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Dzemael Darkhold 29
Aurum Vale 8
Wanderer's Palace 7
Amdapor Keep 8
Pharos Sirius 46
Haukke's Manor (Hard) 10
Copperbell Mines (Hard) 1
Lost City of Amdapor 13
Halitali (Hard) 7
Brayflox's Longstop (Hard) 9
Hullbreaker Isle 3
Stone Vigil (Hard) 32
Tam-Tara Deepcroft (Hard) 13
Snowcloak 4
The Sunken Temple of Qarn (Hard) 1
Sastasha (Hard) 11
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Final total 202
Avg. runs per drop ~13
Estimated drop rate (as of 12/30/14) 8%