I don't think it will be 90%. You forget that cities are more buffered with reserves till plants can be grown. There'll be more resources that can be diverted to growing crops wherever and however one can, infrastructure will last longer in cities, and that kind of thing.

There will also be more violence, turf wars, thedt and destruction of any efdoet to help people, pollution problems to contend with, and that sort of thing.

So the death till will be high. Higher than in rural areas which will have their own unique problems and high death till too, per Capita, but I think 90% is too high. 75 to 80%.

Then again, I think we'll be lucky if we don't lose more than 90% of the current population eventually, as in by the conclusion of collapse, but I took your statement to mean the first big "wump" once the freefall starts. I personally subscribe to the broke staircase idea with several hard "wumps" and a more stable decline otherwise of how it will go.

So maybe I misunderstood what you meant exactly. And maybe it's all semantics in the end.