Why most numbers start with 1

A phenomenological law called Benford's Law or the first digit law, states that in listings, tables of statistics, etc., the digit 1 tends to occur with probability ∼30%, which is much greater than the expected 11.1% (i.e., one digit out of 9).

That has been used by tax experts to detect fraud since any natural data (which are not dimentionless) should exhibit such a distribution of first digits: