OK, everybody knows Apple's (Nasdaq: AAPL) iPad is the King of Tablets, but for how long? The would-be usurpers, those tablets driven by Google's (Nasdaq: GOOG) Android operating system, are catching up fast. The iPad got a head start in the race for tablet domination, but sales of Android tablets built by Motorola Mobility (NYSE: MMI), HTC, LG, Samsung, Acer, and Dell (Nasdaq: DELL) have been accelerating at warp speed.

In last year's third quarter, the iPad dominated with 95.5% of the worldwide tablet market, compared with only 2.3% for the Android tablets. But Android's growth has been phenomenal, and this quarter those tablet sales accounted for 26.9%, versus 66.6% for the iPad.

Fourth-quarter results could get skewed even further away from the iPad. Amazon.com's (Nasdaq: AMZN) budget-priced Kindle Fire, which uses a modified version of Android, starts shipping in November -- just in time for the holiday season.

The market for tablets will be huge. Worldwide shipments zoomed 280% in just one year. With 94% of that market now between them, there's no question that the iPad and the Android tablets rule the roost.

While Apple shipped 11.1 million iPads during the third quarter, and 4.5 million Android tablets shipped out, only 400,000 Microsoft (Nasdaq: MSFT) Windows tablets and 200,000 Research In Motion (Nasdaq: RIMM) PlayBooks left their respective warehouses. The Windows share was 2.4%, and the PlayBook's was 1.2%. It's obvious that Microsoft and RIM have a long way to go to catch up to the leaders.

Google recently rolled out Android 4.0, also known as Ice Cream Sandwich. It is intended to be a mobile operating system that will work with both the smartphone versions of Android and the tablet version, known as Honeycomb. Google hopes that it will motivate developers to produce enough tablet apps to rival the iPad's 140,000.

The Android has come far and is gaining nicely, but Google knows that it's not yet close enough to overtake the iPad. Andy Rubin, a Google senior vice president, said earlier this week that the 6 million Android tablets that are now out there "is pretty healthy, but it is not 30 million [iPads]."

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Fool contributor Dan Radovsky has no financial interest in the companies mentioned in this article. The Motley Fool owns shares of, Apple, Google, and Microsoft. Motley Fool newsletter services have recommended buying shares of Apple, Microsoft, Amazon.com, Google, and Dell, as well as creating bull call spread positions in Microsoft and Apple. Try any of our Foolish newsletter services free for 30 days. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.