In the latest forecast update of the Worldwide Quarterly Tablet Tracker, IDC also raised its 2013 forecast number to 172.4 million units, up from 165.9 million units. And by 2016 worldwide shipments should reach 282.7 million units, up from a previous forecast of 261.4 million units.

"Tablets continue to captivate consumers, and as the market shifts toward smaller, more mobile screen sizes and lower prices points, we expect demand to accelerate in the fourth quarter and beyond," said Tom Mainelli, research director, Tablets at IDC. "Android tablets are gaining traction in the market thanks to solid products from Google, Amazon, Samsung, and others. And Apple's November iPad mini launch, along with its surprise refresh of the full-sized iPad, positions the company well for a strong holiday season."

In addition to increasing the unit totals for 2013, IDC also updated its operating system splits for the year to reflect Android's growing strength in the tablet market. IDC now expects Android's worldwide tablet share to increase from 39.8% in 2011 to 42.7% for the full year of 2012. During that same time Apple's share will slip from 56.3% in 2011 to 53.8% in 2012. Long term, IDC predicts Windows-based tablets (including Windows 8 and Windows RT) will grab share from both iOS and Android, growing from 1% of the market in 2011 to 2.9% in 2012, on its way to 10.3% in 2016.

"The breadth and depth of Android has taken full effect on the tablet market as it has for the smartphone space," said Ryan Reith, program manager for IDC's Mobile Device Trackers. "Android tablet shipments will certainly act as the catalyst for growth in the low-cost segment in emerging markets given the platform's low barrier to entry on manufacturing. At the same time, top-tier companies like Samsung, Lenovo, and ASUS are all launching Android tablets with comparable specs, but offered at much lower price points."

Once again, IDC's increase in tablet shipments comes at the expense of eReaders. IDC lowered its forecast for eReaders for 2012 and beyond. While the front-lit eReader offerings from Amazon and Barnes & Noble have captured the interest of a subset of consumers who prefer a dedicated eReader, most buyers are gravitating toward multi-use tablet products and finding a 'good enough' reading experience on these traditional back-lit tablets. IDC now expects 2012 eReader shipments to top out at 19.9 million units, down from the 27.7 million units that shipped in 2011.