Last March, the NPD Group reported that Apple’s retail market share — its cut of the computers sold in brick-and-mortar stores — had climbed to 14%, a figure that’s roughly double its overall share of the U.S. market and reflects the power of the Apple Store to draw customers and move product.

What NPD didn’t report at the time was the huge growth in Apple’s share of the so-called “premium” computer market — machines that cost more than $1,000.

To some extent, Apple’s (AAPL) share of this market is growing by default. Companies like HP (HPQ), Dell (DELL) and Lenovo ship enormous quantities of PCs at price points between $500 and $750, whereas the only Macintosh that sells for less than $1,000 is the $599 Mini.

Still, Apple’s share of the $1,000-plus retail market was less than 18% in January 2006 according to NPD. By September 2007, it had grown to more than 57%. And in the first quarter of 2008 it hit a record 66%.

This nugget of retail data comes from Joe Willcox, who writes the Apple Watch column for eWeek (see here). He extracted it from an interview last Friday with Stephen Baker, NPD’s vice president of industry analysis.

“Apple has got better distribution than it’s had in the last 15 years,” Baker told Willcox. “They’re in the right spot right now.”

It doesn’t hurt Apple that once you’re in its store, you can’t buy any computer with a screen for less than a grand. “If you don’t give people a choice,” Baker said, “people will spend more.”

[Chart courtesy of eWeek.]