Elephantroom:

I'm sorry,
it's my fault, I found the 2011 North America population figures at this site:
en.worldstat.info/North_America

Now I'm looking at:
en.wikipedia.org/wiki/World_population

and the problem that you was talking about is here again and,
much more big if it must be analyzed longitudinally (along the timeline).
I think I can't help you, but I will open another excel file and if a ratio appears interesting I will post it in your discussion.
I hope that someone else in this forum can help you.
Kind regards.