Why do you think that human drivers are "far from 100%"?

Anecdotally, I can only recall a handful of car crashes involving myself or any friends or family. I can't recall any injuries or deaths due to car crashes among any friends or family. Is it a regular occurence in your circles?

U.S. government data I could find quickly reported that the death rate per 100 million vehicle miles travelled in 2010 was 1, which is a per-mile success rate of 99.999999%. The injury rate was 75, which drops the success rate to 99.999925%.

edit: speling