Well, the fact that those statistics are wrong isnt even in question.
The table linked to in the article shows that between RIM, Apple, Google, Microsoft, and Palm's mobile operating systems, 100% of the US smartphone market is accounted for.
Yet, within the article itself, it's stated that Nokia has a 7.8% share of the US smartphone subscriber base. Exactly what operating system are these 7.8% of american Nokia smartphones running, if it's neither Symbian or Maemo, neither of which appear atall on the list of operating systems that supposedly account for 100% of the market?
A 7.8% chunk missing from the list isnt just a small discrepancy. If that 7.8% share is entire market share (and assumes Nokia's entire US market is dumb/featurephones), then the article's just plain misleading, as it starts off by stating that the statistics relate only to smartphones.

Edit: Also, Nokia's market share slipped 0.3 percentage points. That's not a nosedive at all, let alone a dramatic one - It's less of a decrease than all the other non-android platform's suffered, in fact. Nokia may be losing in the face of Android (in the USA), but those statistics would suggest that theyre losing less badly than everyone else.