They are probably officially tracked sell-through numbers, and given the low European numbers, probably not including a lot of European markets.

Here's the best part though:

To illustrate this, Iwata noted that the number of million-selling third party Wii titles jumped from 12 to 30 during the timeframe covering the end of March to December 2008. Meanwhile, the number third party DS titles which would sell over a million copies also increased from 28 to 49 during that same 9 month period.

At the end of September, there were only 21 third party million-sellers on Wii and 39 on DS, meaning 9 Wii games and 10 DS games crossed that milestone in the holiday quarter.

I'm more curious about this graph:

http://img255.imageshack.us/my.php?image=pszahlenxf3.jpg

http://gamefront.de/

According to this the PS3 is at 15.6 millions not 19.9

That "Europe" only contains UK, Spain, France, Germany and Italy btw.

How big is the market in the rest of the European countries?

yeah the wii def has the potential to sell more than the ps2, however, it is possible that if the economic crisis continues for a long time or (God forbid) gets worse) the sales of video game consoles could drop dramatically

Just look at Scandinavia and Other Europe on VGchartz.

There's also China, Korea, any African sales, etc, that aren't accounted for.

Canada alone would add some millions to these numbers.

Of course this is more or less irrelevant to Iwata's point.

It is probably a bit more than just those big countries, looking at the picture FishyJoe posted their European numbers seem to incorporate parts of Europe with a total population of 335 million people, while the whole of Europe has 493 million. The accompanying words with the picture states Nintendo's European numbers only include countries where Nintendo’s local subsidiaries or its offices are located. So if someone has a list of those countries? 

@Karim: It isn't. PS3 can't play PS2 games.

The point was to show the trend. If you noticed, GBA and PS2 were distributed in similar fashion between the regions, when DS has completely different curve. If Wii follows PS2 in the same way DS follows GBA, you'll notice how Iwata expects growth and where.