Apple Inc.’s (Nasdaq: AAPL) shipments of iPad tablets surged 44 percent to 17 million in the second quarter, giving the company its biggest share of the market in more than a year as devices from competitors lost ground.

Apple’s market share climbed to 69.6 percent in the quarter from 58.1 percent in the previous three-month period, according to a report Tuesday from IHS iSuppli. Cupertino, California-based Apple’s share of the tablet market hasn’t been that high since the first quarter of 2011, when it was 70 percent, IHS said.

With tablet sales predicted by research firm Yankee Group to overtake those of personal computers by 2015, Apple is preparing for challengers for its iPad. Microsoft Corp. (Nasdaq: MSFT) later this year will begin selling its Surface tablet, while Google Inc. (Nasdaq: GOOG) introduced its Nexus 7 device in June. Inc. debut its Kindle Fire tablet last year.

Lenovo, the world’s No. 2 PC maker, also is rolling out a series of tablets, especially in its home market of China. 

“Apple is sending a clear message that it plans to dominate this market over the long term,” said Rhoda Alexander, an analyst at IHS, in a statement today. “Apple’s major media tablet rivals, Google Inc. and Microsoft Corp., hope to challenge Apple in the second half of the year, but will face formidable headwinds.”

Amazon’s share of the tablet market slipped to 4.2 percent in the second quarter from 5.8 percent in the previous three months, IHS said. Samsung Electronics Co. had a 9.2 percent share in the second quarter, down from 10.8 percent.

A new model came out a few weeks before the April-June quarter began. Google’s challenger, the Nexus 7, didn’t start shipping until the third quarter.

Here are the top five manufacturers of tablets in the second quarter, as released by HIS iSuppli on Tuesday:

  • Apple Inc., maker of the iPad, 17 million shipped worldwide, 69.6 percent share
  • Samsung Electronics Co., maker of Galaxy line, 2.3 million, 9.2 percent.
  • Inc., maker of Kindle Fire, 1 million, 4.2 percent
  • AsusTek Computer Inc., maker of Transformer line, 688,000, 2.8 percent
  • Barnes & Noble Inc., maker of Nook Tablet, 459,000, 1.9 percent
  • Other, 3 million, 12.3 percent

 (Bloomberg and The AP contributed to this report.)