I think these are reasonably conservative numbers, and accept them.
Which, if you do the math, means that a thrown knife is lethal way less than a fraction of a single percent. Those are low odds of success.
Ha. Good one. (I bet that high number is actually higher, when you count spears, javelins,sticks, boomerangs, stones from a sling, even big rocks, and atlatls (which are stupid fun to throw, and go super fast and far, if you have not tried one, find some one with one and try it).
The ninja comment, and the 10 or 11 were both joking comments.
I started throwing knives when I was just a kid. I have been throwing them for about 24 years. I have become more than proficient with certain knives. One knife in particular, an old WWII bayonet. Not really balanced for throwing, really handle heavy, but you can get used to just about any balance after thousands and thousands of throws. We had an ugly plug in electric Santa that made a great target for throwing. I could put hundreds of good sticks row without any miss in Santa's head from 50 feet (Santa did neat back flips when that heavy knife hit him in the face and stuck).
If you practice enough you can get very confident a throwing, and judging distances becomes easier.
I throw hawks a ton now, when ever I get a chance, and usually throw a knife too 4 or 5 hours of throwing a hawk and knife in combination is like therapy. My family makes fun of me.
There are knife throwers who can throw no spin, out past 50 feet and stick hard. One of those guys could actually probably kill you with a knife very very easily if you were not paying attention. If you see a guy that far throw something shiny at you in any kind of a war or fight situation your natural instinct will be to duck or move. You probably won't be standing in the same place you were when the knife was thrown (if you don't believe this, just watch the Bush shoe ducking video on you tube, Bush ducked both of those loafers with cat like reflexes).
If you were standing in my back yard, And not paying attention, I could probably kill you with my bayonet out to 60 feet (because that is where I run out of space, what with the fence and all). A bit closer the odds go way up for me skewering you like a kebab, again if you aren't paying attention. If I am within 25 feet, I might be able to stick you even if you are paying attention.
I am much better with my hawk, and can throw it while moving forward and backward And have gotten quite good at judging distances with it. (it is easier to throw than a knife in my opinion).
I am no pro thrower, or master at it. And I would only throw if I had to, and if I had a back up weapon, like another knife to use when I missed, or another hawk.
Realistically, If I had a knife and a hawk (ya, right, what are the odds of that outside a end of the world, Zombie, or RedDawn type situation), I would use the hawk or knife throw when I was closing with some one. Even if you don't kill them with the throw, you can distract and cause pain. I can be reasonably sure that if I throw a hawk at you from within 15 feet of you while I am closing the distance, you will be hurt, or at least severely distracted. The strategy seemed to be helpful in actual war against armed opponents (warriors use small throwing axes to disrupt the line of opposing warriors holding shield and swords etc).
Heck it might even work against a ninja too, especially mall ninja's, they don't stand a chance!