I used to record my drops, just to make it less boring killing thousands of monsters, and I was interested in the ratios of items, because as I said before, killing thousands of monsters can be quite boring... I have a list of the drops I got from 20k abby demons, among others. Whips were about 1/300, and that ratio stayed the same from like 5k killed to 20k, so abby whips are very close to 1/300 (although it might be different now, after hearing people whine so much about not getting any)... I haven't killed any for 2 months so its possible jagex made whips rarer. I also got a d med every 5k kills, and I got 2 spears in the first 1k, but didn't get anymore after that; just shows how random it can be. Also didn't get any shield halfs. You would need to kill millions to find the exact rarity of dragon drops... so it's impossible to know exact drop rates, since even if you got a ton of people to work together, no doubt some of them would lie or make a mistake. Jagex should tell us the rates when we ask, I don't see how it could affect the prices of dragon items, but thats just my opinion...