You can now buy a typing tutor program which allows you to identify your individual error rate per finger, over a period of time.
The only data I can find indicate an error distribution of 2,4,1,2,0, 0,1,2,4,14 %.
I’m guessing this may vary significantly between individuals but it is an interesting measure of one’s physiology, which might in itself allow identification of an individual. Perhaps the motor homunculus in one’s motor cortex reflects these figures.
Today’s invention however is to gather the information for an individual who has not yet learned to type and then reprogram their keyboard so that the most frequently typed letters in one’s language, eg E, are placed close to one’s most accurate fingertip (and vice versa).
(There would be little point the indvidual whose map is shown above using his right, little finger to type E, for example).