Is there any information on how the mining power is distributed geographically? I.e. where the computers are located that do the work.

This is important as one measure of centralization of the system, and thus of the trust in the proof-of-work concept.

Of course, there are many different ways to measure centralization, but that's not part of this question.

Thank you!

PS: I'm open to suggestions for better tags of this question.