Diaspora just means dispersed people. It doesn’t convey any time frame in and of itself
Yes, exactly, hence “per all time, that are still alive” because it’s measuring the current number of American-born residents of each country, compared to the residents from said country in America.
As of what year?
Edit: id also like to point out there are diaspora maps for time frames, so just posting a map with that word is as best trying to misleading or make a statement. Otherwise, that information would be freely available. That’s how data works.
That’s an entirely different thing than “per unit of time”. It’s a valid question, turns out there isn’t an answer, but some very basic searching linked me to the original map as released: http://cf.datawrapper.de/dduui/2/
To your edit, sure, there are diaspora maps for timeframes. Those are called immigration/emigration maps, because the acts of which grow or shrink a diaspora.
