By Aidan Malley

Published: 12:05 AM EST

Apple dropped slightly to fifth place in rankings of US computer sales during the fourth quarter of 2006, according to preliminary Gartner data obtained by AppleInsider.

The Mac maker fell a full percentage point to 5.1 percent of the domestic market between the third and fourth quarters of the year, trading places with Toshiba, which climbed from 5.1 to 5.3 percent. Apple remained out of the top five in the world rankings, but a similar set of data released by IDC on Wednesday puts its international share at 2.4 percent.

Shipments of Macs in the U.S. also dipped significantly from 975,000 US systems to 808,000, indicating a genuine slowdown in sales for the Cupertino-based company following a stellar back-to-school quarter. Dell remains in command of US sales at 29.1 percent but is bleeding rapidly, having lost 3.1 of its share. Most of this was gained by Hewett Packard, which jumped from 23 to 25.3 percent, Gartner said.

In spite of the seeming downturn, Apple nevertheless maintained the highest year-over-year growth of any of the top five computer builders operating in the Americans, soaring 30.6 percent compared to Toshiba's gain of 22.3 percent over the same timeframe.

Gartner also noted that the US climate for PC sales was especially harsh: total shipments for the year actually sank 3.2 percent compared to 2005, with Dell suffering the worst losses as it gave up a staggering 17.3 percent. The overall market at home and abroad suffered in large part due to competition with hot-selling electronics such as flat-panel TVs and the Nintendo Wii, Gartner analyst Mikako Kitagawa said. PC makers were also forced to cut prices to spur interest in their systems for buyers who would otherwise have waited for Windows Vista.

"PC price erosion was a defining feature of the quarter," Kitagawa said.