Another source of population numbers for various countries is the US Census Bureau web site, http://www.census.gov/ipc/www/idb/idbr200707.html. USCB does their own scrubbing of the data. At best this might be characterized as 'untainted by UN political correctness', but it is at the very least a source having different workers scrubbing the data. I noticed from the Release Notes that the former French colonies are now called overseas Departments, and their populations are included in the total for France in Europe. USCB does not do its own data collection on other countries (of course not, only CIA might try to do that).

If there are discrepancies for various sources and for various countries, I suggest one ask whether they are large enough to change the main conclusions. For population of USA, I guess no available population estimate knocks USA out of the well-to-do group.