This looks very Eurocentric to me. China and the various Indian empires are getting short-shrift here, at least from an economic and military power perspective.

This looks very Eurocentric to me. China and the various Indian empires are getting short-shrift here, at least from an economic and military power perspective. It's a cool diagram, but what was the methodology used to generate this? EDIT: Makes sense in the context of the times. Would be interesting to see an updated version, based on modern historical estimates.