I don't have exact statistics for any of this.
The fall is not what kills you, it is the sudden deceleration at the end. The only thing that can cause a change in speed is another force being applied to you. During the fall, the 2 forces of air resistance and gravity are acting on you constantly in opposite directions, with gravity causing more and more acceleration until you reach terminal velocity, at which the air resistance cancels the gravity out & you fall at the same speed the rest of the way.
The air you fall through, while offering resistance, lets you pass through it (almost) as easily as if you were falling through nothingness. However, the ground is not as much of a pushover; it does not let you pass through it as the molecules are too packed together. This means that, once you reach the ground, unless you break it & fall through the floor, you go from moving at tens or hundreds of miles (or km) per hour to essentially 0 in a second or 2. Because of inertia, your body does not want to slow down that fast, so it puts up a lot of resistance. What ends up happening is that some of your body continues falling while the rest of it has already stopped, and so your hands end up hitting the ground, too, your head ends up by your feet, and, if you were falling fast enough, your lungs end up hitting your kneecaps. You pretty much die by being squished to death.
The more tightly-packed the ground medium, the faster you will decelerate upon landing and the lower velocity you have to be at before you hit the ground to die. This is because a looser-packed medium lets you fall for a little longer before you stop moving, although it also means you can die before you stop moving, seemingly invalidating the premise of this answer that it's "not the fall that kills you". Even a split second of extra falling time could mean the difference between life & death. For water or lower-pressure ground, such as an airbag or loosely-packed dirt, you have to be moving at a much higher speed to die. Of course, this also depends on things like your height and how tightly-packed your insides are. A younger person would usually have to land at a higher speed to die.
Another note is that, under certain conditions not usually found on Earth, the fall can kill you before you hit the ground. If you have a sudden change in acceleration, such as going from a high-pressure air system to a sufficiently lower-pressure one or vice-versa, you could end up being squished & die. The change in speed, again, determines whether you die.
