back a year ago when they were introduced about 5 would drop each run, back now anet nerfed the droprate and the only drop once in 5 runs, at least thats what im getting.
An observation I've made after farming lots and lots of these things is that new characters and characters that don't farm much seem to have better luck in the first 5 or so runs than older characters who have farmed a lot. It's almost as if characters have a handful of IDS "reserved" for them, but once they are gone (of if your character has some kind of farm flag on them) you get the crappy drop rates.
For example (and to get max use out of me screenies ), my paragon has never farmed a thing in her life but has had really good luck IDS farming:
An observation I've made after farming lots and lots of these things is that new characters and characters that don't farm much seem to have better luck in the first 5 or so runs than older characters who have farmed a lot. It's almost as if characters have a handful of IDS "reserved" for them, but once they are gone (of if your character has some kind of farm flag on them) you get the crappy drop rates.
For example (and to get max use out of me screenies ), my paragon has never farmed a thing in her life but has had really good luck IDS farming: