I'm not sure where you want to go with your question. But I assume that you know that Nokia never released sales numbers for the N900 to the public. The only people able to answer your question would be Nokia insiders.
28 May, 2010 LONDON: Nokia sold less than 100,000 top-of-the-range N900 smartphones in its first five months on the market, researcher Gartner said, indicating it has yet to mount a serious challenge to the iPhone and Blackberry. The chunky computer-like handset -- with slide-out keyboard and a touch screen -- has found support among hard-core technology specialists but failed to attract a wider audience.