Here's the one from today (in English): https://www.rki.de/DE/Content/InfAZ/N/Neuartiges_Coronavirus...
The interesting table is on page 6, where there's the percentage of ventilated patients on ICU, which is 73%, so we know most ICU patients are ventilated, which means we can treat someone being on ICU as roughly equal to someone being ventilated. Right below is the number of discharges from ICU, and the percentage of deaths, which is 30% of all discharges. Since almost all ICU patients end up being ventilated, we can conclude that these about 30% of deaths mostly happened on ventilation, and most of the 70% recoveries also happened on ventilation.
I know that my calculation doesn't exactly result in the real percentage of deaths on ventilation, but the error range of my estimation does not allow the actual percentage of deaths on ventilation to even come close to 90%.
This is where your logic fails. Most patients in the ICU at this point in time are ventilated. That doesn't (necessarily) mean that most patients that went to the ICU were ventilated. Those that are ventilated will stay in the ICU for weeks. Those that aren't might only be there for a few days.
That’s in New York, and probably because they only put the really worst cases on ventilators because there weren’t enough ventilators. In Germany, that number of deaths on ventilators is at around 30%. This shows that this quota is entirely useless to make your argument, and that maybe you should curb your intuition a bit when it comes to estimating percentages of potentially saveable people, especially if those estimates are then used to effectively sentence people to certain death.