NPD data shows Feb. Mac sales slowdown before Apple's MacBook Pro refresh

The latest domestic retail tracking data from the NPD Group shows that U.S. Mac sales were up 16 percent year over year in January and February of 2011. As noted by analyst Gene Munster with Piper Jaffray, the consensus view on Wall Street is that Apple will report Mac sales up 22 percent year over year for its March fiscal quarter.

While the number is low, it also represents two months before Apple released its new line of MacBook Pros, which arrived in late February. This suggests that sales may have dipped before the anticipated refresh. Supporting this theory, U.S. Mac sales were up slightly more — 20 percent — in January.

In addition, international Mac sales tend to have stronger year over year growth than Apple's U.S. sales. Because of this, Munster expects Mac sales to be up between 20 percent and 25 percent in the quarter, a number that would be in line with Wall Street's expectation of 22 percent.

And as devices like the iPhone and iPad continue to grow in popularity, the Mac also becomes a less important component of Apple's business. Munster noted that he estimates Mac revenue will represent just 21 percent of Apple's overall revenue in calendar year 2011.

If Mac sales grow between 20 percent and 25 percent year over year, Apple would sell an estimated 3.5 million to 3.7 million units in the three-month frame. Wall Street generally expects Apple to report sales of 3.6 million Macs in the quarter that ends in March.

Munster also noted that NPD data suggests sales of between 9.8 million and 10.3 million iPods for the March quarter, which would a reduction of between 5 percent and 10 percent from a year ago. Wall Street generally expects iPod sales to be down about 6 percent year over year.

International iPod sales are a larger mix than international Mac sales. As a result, NPD's domestic tracking data carries a slightly larger margin of error in projecting iPod sales.

In the previous, holiday quarter, Apple sold a record 4.1 million Macs, helping the company to earn its best-ever $26.74 billion in revenue. Mac sales were helped significantly by the popular MacBook Air, of which more than 1 million were shipped.