Since Amazon.com (Nasdaq: AMZN) simply won't give us a number on its Kindle Fire shipments, CEO Jeff Bezos really leaves us no choice but to play guessing games with third-party sources. That also happens to be a habit that rival bookseller and tablet purveyor Barnes & Noble (NYSE: BKS) picked up on too. Tablet top dog Apple (Nasdaq: AAPL) is one of the few players that isn't coy about handing out its digits, but when you're king of the hill, who wouldn't want to flaunt figures like these?

iSuppli has released its latest batch of estimates on the state of the tablet market as of the fourth quarter. The market-intelligence specialist estimates that Amazon shipped 3.9 million Fire tablets in that timeframe, promptly jumping to claim the silver medal with a 14% market share.

Source: iSuppli.

The overall market grew from 17.4 million units to 27.1 million units, a 55% bigger pie. Apple's shipments grew 39% to 15.4 million, but that growing base made Cupertino's market share slip. Samsung's 2.1 million tabs moved was just an 8% increase, while B&N's units soared by 156% to 1.9 million tablets on the heels of its new Nook Tablet.

Interestingly, iSuppli analyst Rhoda Alexander said Apple's biggest competitor was itself, as the iPhone 4S launch provided a competitor for prospective buyers' disposable dollars. Alexander attributed the surge in Google (Nasdaq: GOOG) Android tablets to the Fire and Nook, since other Android players were forced to cut prices to compete, helping to spur sales.

The researcher expects the iPad 3 demand to outstrip supply for several months once its released. With price competition heating up in the Android arena and threatening profitability, iSuppli expects vendors to start considering Microsoft (Nasdaq: MSFT) Windows 8 more seriously, and thinks the tablet market will see a slew of Windows 8 and ARM Holdings-based tablets hit the market late this year.

Total tablet shipments for 2011 came out to 65.2 million, topping the company's forecast of 64.7 million. Compare that to the 17.4 million overall shipments in 2010 and you'll see 274% growth – in other words, shipments nearly quadrupled.

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