[lkjhgfvhjk]

Although those who don't climb Everest have a 100% mortality rate

(Perhaps 99.9999% if you include the Dalai Lama)

[pingswept]

Historically, it's closer to 94%. In rough numbers, there have been around 100 billion humans [1], and only around 6 billion of them are left, even if you count the Dalai Lama.

[1]: http://www.prb.org/Articles/2002/HowManyPeopleHaveEverLivedo...

[stratomorph]

Well, 94% mortality and 6% for which there is insufficient data to draw a conclusion. We'll have to wait a while to be sure if any of them are immortal.