There are some strong taboos against extending your life. That is visible in some answers here. The taboos result from a longstanding tradition and have the purpose to make you accept death because you can't avoid it. This can also be observed sometimes in disasters, shipwrecks and so on, some people struggle to survive and others just sit down to die.

However you can outwit the taboo with clever asking. In the poll at the beginning, 39% have voted "never", which means that 61% want to die by old age. However I guess this result would be different when you formulate the question differently, like this:

"You are 78 years old and hospitalized because you're suffering from the usual age diseases, such as mental confusion, rheuma, Parkinson, and incontinence. Now the doctor approaches your bed and tells you:

'We can keep you alive for a while but you'll die within the next 5 years. But there is a cure. I can give you a pill against the Alzheimer, Parkinson and whatever else you have, and you can then immediately go home. There's only one catch. The cure works by removing the physical effects of your age, and thus gives you again the body and mind of a 30 years old. Shall I now give you the pill, or not?'"