A blog or two ago I quoted the huge gap in average annual income beteen

Mexico and the U.S., using numbers I got from the BBC News country summaries

http://news.bbc.co.uk/1/hi/world/africa/default.stm

I find myself wondering about the history of that gap. Obviously it has

always been large. Is it getting larger? Smaller? Or what? Did NAFTA

make any difference to it?

I dimly recall reading somewhere that NAFTA did indeed close the gap for a

while, but that the gap has since widened again to some kind of historical

norm. The memory is vague, though.

Can anyone with better command of international-economic databases than I

have clear this up for me?