Ok, so lets say you have a data set that consists of items that tend to cap at 2000. Already, half of all possible numbers begin with 1.
I think 1 is special, in any base, because it's the first digit used when a new digit gets added. If you're talking about quantities that vary easily by, say, thousands, once it crosses the 10,000 threshold the first digit changes much more slowly.
There's more to think about here for sure, though.
It works in any base, you can extend Benfords law to other bases easily.
Try it on a set of numbers in base 10, then convert them to base 16 and check the percentages you get. They still follow the same pattern, but of course there are more slots and the individual percentages are lower because of that.