Apple barely clung on to half of the global tablet market in the third quarter, reaching an enviable 50.4 percent but nonetheless down 15.1 percent from the previous quarter, according to a new IDC report.

Samsung was happy to make up most of that difference, attaining 18.4 percent of worldwide market share by shipping 5.1 million Android tablets, up 115 percent from the previous quarter.  Ryan Reith, program manager, IDC’s Mobile Device Trackers, said consumers were attracted by the range of price points and model choices.

Amazon also was responsible for some of Apple’s slip. It didn’t offer tablets a year ago, but its worldwide market share rose from 4.8 percent in 2Q2012 to 9 percent in 3Q2012 despite being available only in theUnited States.

Lenovo and ASUS were the other companies that also took market share from Apple, primarily due to ASUS’ Google-branded Nexus 7 device and Lenovo’s growth inChina, according to IDC. See the chart below for a visualization.

IDC points out that Apple’s sales were slowed because consumers were waiting for the iPad mini’s release in the fourth quarter. Tom Mainelli, research director, Tablets at IDC, said Android will remain a strong competitor: “Now that the new mini, and a fourth-generation full-sized iPad, are both shipping we expect Apple to have a very good quarter. However, we believe the mini’s relatively high $329 starting price leaves plenty of room for Android vendors to build upon the success they achieved in the third quarter.”

Tablets are a growing market overall, expanding 6.7 percent in 3Q12 over the previous quarter and 49.5 percent year-over-year.

“Competitors are turning up the pressure on market leader Apple,” Reith said. “With the recent introduction of a number of Windows 8 and Windows RT tablets, consumers now have a third viable tablet platform from which to choose. However, price points are critical in tablets, and Microsoft and its partners will have a tough time winning a share of consumer wallet with price points starting at $500.”