Template:Legendary drop rate
From Diablo Wiki
Legendary materials drop more often on higher difficulty levels. Their drop rate was tripled in Patch 2.0.4 shortly after Reaper of Souls' release, making them all much easier to find. The figures are the percent chance the legendary material (or Deaths Breath will be dropped by a valid source. All legendary materials except Adventurer's Journals and Griswold's Scribblings can only be dropped by Unique (purple) bosses of a certain type. See the legendary materials article for full details.
|Legendary Material and Deaths Breath drop rates|