Fuzzy math in Apple harvest?

Apple Computer saw its personal computer shipments jump considerably during the first quarter, as we reported Friday. The numbers got even better this week.

That's because IDC, which published its first quarter PC shipment figures last Friday, left out a chunk of Apple shipments from its U.S. tally. It said at the time that Apple turned out 450,000 units in the United States during the quarter. But on Monday it quietly revised that figure upward to 565,000. The increase in Apple's unit shipments bumped it up to a 3.9 percent share of the market, making it the fifth largest computer maker in the U.S. for the quarter. Our story now reflects that change.

Apple would still have to make up some ground to catch Gateway or IBM, the third and fourth placed PC makers in the U.S. IDC says Gateway and IBM shipped 830,000 and 627,000 units, respectively, during the quarter.

But the Mac maker's whopping 45.5 percent year-over-year increase in shipments, as reported by IDC, was surely the envy of all. The next best, Dell, mustered shipment growth of just over 8 percent.

For its part, market researcher Gartner had Apple in the fifth spot in the United States all along.