I also have a hard time finding this map to be pure coincidence:
Notice how when you go from Guatemala to Mexico there's a drop, then from Mexico to the US there's a drop, then from the US to Canada there's a drop?
Then South Africa to Zimbabwe there's a drop and then a drop from Zimbabwe to Zambia.
Too bad not all of the countries are represented because I think it would paint a pretty clear image.
*edit: missed Brazil down in SA but yeah that too.