In mature markets where tablet adoption has already accelerated to a rapid degree in recent years, future growth will be more muted. That's according to the projections released Thursday from IDC.

Faced with growing competition from larger smartphones and the prospect of new categories such as wearable devices diverting consumer spending, International Data Corporation (IDC) Worldwide Quarterly Tablet Tracker "modestly lowered its tablet forecast for 2013 and beyond."

Here's how the numbers shake out.

IDC now expects worldwide tablet shipments to reach 227.4 million units in 2013 (that's down from a previous forecast of 229.3 million). Despite the modest forecast change, the shipments IDC expects for 2013 remain 57.7% above 2012 shipments.

So not withstanding slowed growth, the growth will continue through at least 2017 when worldwide shipments are expected to hit 407 million units.

"A lower than anticipated second quarter, hampered by a lack of major product announcements, means the second half of the year now becomes even more critical for a tablet market that has traditionally seen its highest shipment volume occur during the holiday season," says Tom Mainelli, Research Director for Tablets at IDC. "We expect average selling prices to continue to compress as more mainstream vendors utilize low-cost components to better compete with the whitebox tablet vendors that continue to enjoy widespread traction in the market despite typically offering lower-quality products and poorer customer experiences."

Source: IDC