Surely it can't just be number present. It must be some proportion.

Looking through the comments, it looks like it's per 1000 Internet users.

My question was mostly rhetorical, really, to make the point that without units listed on the map it becomes almost entirely useless. Sure, it gives some idea of proportion. I can tell that the US has more GitHub users in a certain group than Canada does in that same group, but it's lacking a lot of context. What group (Internet users, per capita, etc.)? 11.5 out of how many (out of 100 would be significant, out of 10000 not so much).

It shouldn't be necessary for people to have to search through the comments to find this context. What if I want to share the map? Am I expected to caption it myself when I share it?

Sorry to kind of go off, I know it's not really that significant. But it's such an easy thing to include units with your data, and I feel like it's necessary to emphasize its importance in this community while it's still young and developing.