The latest projections, published on Tuesday by IDC, call for tablet shipments to reach 229.3 million units this year, up from 144.5 million a year ago. That will likely be enough to push tablets ahead of notebook computers.
And by 2015, IDC predicts that tablets will out-ship all PC units, including desktops. The prediction comes as tablet sales continue to rise, and the PC market remains in a slump.
Those struggles were predicted by late Apple co-founder Steve Jobs in 2010, when he said the debut of the iPad signaled the beginning of a market-wide transition to a post-PC era. At the time Jobs believed that traditional PCs would remain, but their presence would be diminished over time as fewer users would need their specific abilities.
"The transformation of the PC to new form factors like the tablet is going to make some people uneasy because the PC has taken us a long ways," Jobs said at the AllThingsD conference. "The PC is brilliant? and we like to talk about the post-PC era, but it's uncomfortable."
To date, Apple's iPad has been the dominant device in the tablet market. But current growth is being driven largely by low-cost Android devices, IDC said.
The firm believes that the average selling price for tablets will drop 10.8 percent to $381 this year. That's still above the $329 entry price of the iPad mini, but well below the $499 starting price of the full-size iPad.
"Apple's success in the education market has proven that tablets can be used as more than just a content consumption or gaming device," said Jitesh Ubrani, research analyst for IDC's Worldwide Quarterly Tablet Tracker. "These devices are learning companions, and as tablet prices continue to drop, the dream of having a PC for every child gets replaced with the reality that we can actually provide a tablet for every child."
Reflecting Apple's success with the iPad mini, and the popularity of low-cost Android tablets, IDC believes that tablets with screen sizes of 8 inches or less will account for 55 percent of shipments this year. That's expected to increase to 57 percent by 2017.
And while tablets sized between 8 and 11 inches were 73 percent of the market in 2011 before the introduction of the iPad mini, that market segment is expected to shrink to 37 percent by 2017.
IDC's market-wide forecast comes on the heels of a projection by noted analyst Ming-Chi Kuo of KGI Securities, who said last week that he believes iPad shipments could see their first-ever year-over-year decline in the second quarter of calendar 2013. To date, Apple has managed to grow iPad shipments every quarter since the launch of the first model in 2010.
But Apple has signaled that it is not planning to introduce any major new products ??namely updated iPads or iPhones ??until this fall. As consumers wait for new devices, some, such as Kuo, expect that shipments will fall.