That is certainly possible but I don't see why they would stop citing NPD if they were just providing USA data. A source told me the Xbox attach rate ended up around 9.5 games/system and the X360 has a more diverse lineup of titles so I wouldn't be surprised if the figures were about 8.7 worldwide. Sony's figures include PSN downloads anyway (not that its a huge figure) so its never going to be a completely clean comparison anyway.
By the way, Nintendo's half year presentation is amazing - you should all check out the highlights it has relevant data for all six systems in all three regional markets. I just wrote it up http://news.vgchartz.com/news.php?id=5719
People are difficult to govern because they have too much knowledge.
When there are more laws, there are more criminals.
- Lao Tzu
