The International Data Corporation report came as research firm Forrester forecast that tablet sales would rise rapidly worldwide in the years ahead.
Global tablet shipments in the second quarter of this year declined 9.7 percent from the prior three-month period, according to IDC.
However, tablet shipments climbed nearly 60 percent to 45.1 million units when compared with the same quarter a year earlier, IDC reported.
A quarter-over-quarter slowdown in sales was expected given that Apple did not unleash a new version of its coveted iPad early in the year as it had in the past, according to IDC analysts.
"A new iPad launch always piques consumer interest in the tablet category and traditionally that has helped both Apple and its competitors," said IDC tablets research director Tom Mainelli.
"By the fourth quarter we expect new products from Apple, Amazon, and others to drive impressive growth in the market."
Worldwide tablet sales will reach 381 million units in the year 2017, with business accounting for 18 percent of the purchases, according to a Forrester forecast authored by JP Gownder and Michael O'Grady.
"We believe tablet sales and penetration will continue to grow rapidly," Gownder said Monday in a blog post.
"In developed markets, they will streak past 'mass market' status to become what we term 'mainstay' devices - a third form factor carried by most online consumers."
Apple shipped 14.6 million iPads during the second quarter of this year in a 14.1 percent drop from the same quarter last year, according to IDC.
Meanwhile, sales of tablets grew for Apple rivals Samsung, Asus, Lenovo, and Acer, market figures showed.
"The tablet market is still evolving and vendors can rise and fall quickly as a result," said IDC mobility tracker program manager Ryan Reith.
"Apple aside, the remaining vendors are still very much figuring out which platform strategy will be successful over the long run."
While Apple remained the top tablet maker, Google-back Android mobile software used by a variety of the California company's competitors accounted for 62.6 percent of the market in the second quarter, according to IDC.
"To date, Android has been far more successful than the Windows 8 platform," Reith said, in a reference to Microsoft operating software.
"However, Microsoft-fueled products are starting to make notable progress into the market."
About two million Windows-powered tablets were shipped in the second quarter in an increase of more than five times from the same three-month period last year, according to IDC.
Microsoft on Monday knocked $100 off the price of high-end versions of its Surface tablet, which is competing against Apple's iPad and devices that use Google's Android system.
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