For example, take a list of population counts for each of the more than 8000 cities in Spain. Like the one on the left. Without actually seeing that whole list, approximately what percentage of those numbers do you expect to start with the digit one?
You could reason that since the first digit could be any from 1 to 9, then a number will start with a specific digit about one in nine times as well. Or about ~11%. You know, on average.
That seems a reasonable and logical guess, and yet it turns out that almost one third of the numbers on this list start with the digit ‘1’!
Check out that link. That site shows something else too. It doesn't just apply to this particular list of numbers. Nor does it only apply to lists of population counts. There are many, many numerical data sets out there where this Law — also called Benford's Law — applies.