If your guess is closer to 4 or 5 than the actual 2,2 you might want to spend an hour on this lecture by Swedish professor, statistician and physician Hans Rosling. (It's held in English - with an amusing Swedish accent - and subtexted in Swedish.) He treats data and statistics in a more artful and entertaining way than you are probably used to (which has turned Hans Rosling into a Ted talks celebrity).
Most of us don't have updated knowledge on population growth, health, poverty and other important global trends, which is a shame.
And the picture is not as bleak as some of us might suspect.
Please enjoy.
Sun Mar 02, 2014 at 11:31 AM PT: The previous link only works in Sweden for copyright reasons. Sorry!! This shorter presentation covers some of the same material.
http://www.ted.com/...