Well it's definatly in the kilos for me, cos i smoke at least 7g a day for the last 4 years, so that about 2 oz every week, and a key is only 36 oz, so yeah, almost 2 kilos a year i supose, im not sure if that math works out, im not too good with it, but damn, i smoke alot, and thats only in the last 4 years. Let alone what i smoked before i started smoking havily.