It's really hard to generalize, because it depends a great deal on what you hit. People generally survive a fall from the second story of a building (12-15 ft?), but generally not from the 4th (32+ feet?). A fall from the third story approaches your 50-50 scenario. But falls from a multistory building are generally to a hard surface: sidewalk or road. Fall into water, and you have a good chance of survival at a height of 100 feet or more. Professional "cliff divers" regularly dive at heights up to 110-120 feet, and not only survive but walk away afterwards.
"It's not the fall that kills you, it's the sudden stop at the end!"
![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
That's not just a joke; if the stop at the end isn't so sudden, you can survive falling a lot farther. There was a case where a Russian female pilot ejected, her parachute didn't open, but she survived (with a broken pelvis) hitting at terminal velocity, when she hit a sloping snowbank on a glacier. Updrafts and landing in haystacks have also been known to let people survive very long falls. Of course, as you might imagine, this is *extremely* rare.
The Worst-Case Scenario Survival Handbook says "It is entirely possible to survive a high fall (five stories or more) into a dumpster, provided it is filled with the right kind of trash (empty boxes are best) and you land correctly. [Because your body will fold into a "V" upon impact, you want to land on your back. Landing on your stomach will likely break your back. Do not try this at home!
![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
]