15 to 50 percent. It doesn't seem clear. I'm not a medical professional, but I have been wondering if all the hand-wringing about vents is justified given that most people who get to that point die. It would be interesting to see more granular numbers. What if you find that certain preexisting conditions change the survival rate from 50, or 15 down to 1-2 percent? It would help make decisions about allocating vents in the event of a shortage.