Barclays Capital said Apple Inc. (NASDAQ: AAPL) launched new MacBook Pro products on February 24, which boosted the March NPD data. Similarly, the brokerage expects a re-acceleration in May data driven by new iMacs launched on May 3.

NPD US data indicates that Mac units grew 9 percent year-over-year in April following 47 percent year-over-year growth in March and 12 percent year-over-year growth in February with the significant deceleration in Mac sales driven by the timing of the MacBook Pro launch last year (April 13, 2010) driving a tough compare (Mac shipments were up 39 percent year-over-year in April 2010 versus up just 7 percent year-over-year in March 2010).

Note that Apple already launched new MacBook Pro products on February 24, 2011 which boosted the March Mac growth figure. While 9 percent year-over-year growth is well below our estimate for 22.5 percent year-over-year Mac unit growth for calendar second quarter we had expected to see a slowdown in April before a re-acceleration in May driven by new iMacs launched on May 3, 2011, said Ben Reitzes, an analyst at Barclays Capital.

Reitzes said, according to NPD weekly data, Apple saw year-over-year unit growth in Macs of 35 percent year-over-year for the first week of May after a growth of 22 percent year-over-year average over the previous four weeks with only half a week of new iMac sales included.

Reitzes said NPD monthly data shows Mac average selling prices declined 3 percent year-over-year with an overall Mac average selling price of about $1,400 in April versus just $737 for the average PC. Dollar sales for Macs were up 6 percent year-over-year in April versus market growth of 3 percent.

Apple held 16 percent unit share (up 1 point year-over-year) and 30 percent value share (up 1 point year-over-year) in April. We believe that Apple will continue to gain share in Macs over the long-term even as the iPad grows, said Reitzes.

Reitzes said total PC unit volumes were indicated flat year-over-year for the week of May 1 to May 7 with Mac unit volumes indicated up 35 percent year-over-year. Mac shipments were up just 4 percent last week (Easter Sunday created one less shopping day) with a growth of 22 percent year-over-year average over the previous four weeks.

Reitzes believes the re-acceleration in Mac unit growth this week was driven by the launch of new iMacs on May 3 (Apple desktop units were up 45 percent year-over-year the week of May 1 to May 7 versus down 23 percent year-over-year the week prior). NPD’s weekly data is a small subset of its monthly data; weekly data does include Apple store sales but not sales from Apple.com.

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