In almost any large set of real numbers, more of them start with 1 than any other digit

Look at river lengths, stock prices or street addresses: about 30% begin with the digit 1, shrinking all the way down to under 5% for 9. Frank Benford documented the pattern across thousands of datasets in 1938, and auditors now flag fabricated financial figures when they deviate from it.

— Frank Benford, The Law of Anomalous Numbers — Proceedings of the American Philosophical Society, 1938