Interpretation of terms is a significant issue, in terms of what qualifies as a computer and whether you fulfill terms like "routinely," "commonly," and "growing." Karo has covered that first bit.

As I score it, 9/31 are right by a generous interpretation of terms, maybe a few more depending on areas I do not know well or with very broad uses of "portable computer." Do cell phones outnumber land lines yet? By a stricter interpretation, 2/31 (lighter and thinner portables, many digital objects).

Rather than belabor Karo's point, I will note that we keep defining "computer" up, such that most of us do not think of MP3 players and cell phones as computers. You can, however, buy reasonably priced cell phones that are more powerful computers than the desktop I had in 1999.