outsider:
For the same reason we have 33,47, 68, 91, etc. Has to do with tolerances I think.
R Color Codes
Very interesting! Although, I was thinking that tolerances are just tolerances... linked to uncertainty. So the uncertainty would cover the value of a practical resistor. I was thinking the actual mean value of a resistor won't be chosen (eg. 221 ohm) to meet a particular tolerance value, right?