Apple iPad
The worldwide tablet market share of Apple iPad dropped to 39.6 percent in the first quarter of 2013. Apple

Although the worldwide tablet market share of Apple's (NASDAQ: AAPL) iPad dropped to 39.6 percent in Q1 of 2013, the company outperformed International Data Corporation’s, or IDC's, first quarterly projections for this year, shipping 19.5 million units compared with a forecast of 18.7 million units.

Apple posted year-over-year growth of 65.3 percent in Q1, but it still saw its market share of the total tablet market dip from 58.1 percent a year ago to just under 40 percent this year. However, with shipments of 19.5 million iPads, Apple still shipped more than double Samsung's 8.8 million units.

Samsung's year-over-year tablet sales growth of 282.6 percent helped it take 17.9 percent of the total worldwide tablet market share, compared with 11.3 percent during the same period in the previous year.

According to IDC, Samsung performed above expectations and grew its shipments in the fourth quarter as the company's smaller-size tablets began to gain traction in the market.

The strong performance of both market leaders, Apple and Samsung, helped drive total shipments to an impressive 49.2 million units for the quarter, with growth at 142.4 percent year-over-year in the first quarter of 2013, the IDC report said.

Tablet Market Share
Top five tablet vendors, shipments and market share, first quarter 2013 (shipments in millions) IDC Worldwide Tablet Tracker, May 1, 2013.

"Sustained demand for the iPad mini and increasingly strong commercial shipments led to a better-than-expected first quarter for Apple," Tom Mainelli, research director of tablets at IDC, said. "In addition, by moving the iPad launch to the fourth quarter of 2012, Apple seems to have avoided the typical first-quarter slowdown that traditionally occurred when consumers held off buying in January and February in anticipation of a new product launch in March."

ASUS managed to move into the Number Three vendor spot as it continued to see decent tablet demand from the highly marketed Nexus 7 device. However, the report stated that with Google's I/O conference right around the corner and expectations of an imminent device refresh, the company will need to find a way to sustain its momentum.

While Amazon fell to the No. 4 position with a 3.7 percent market share with 1.8 million units shipped, Microsoft took the fifth spot with an 1.8 percent market share and 0.9 million shipments.

iCharts

IDC said Microsoft entered the top five for the first time as shipments of its Surface RT and Surface Pro tablets combined for a total of nearly 900,000 units. Many of those units were Surface Pro, which the company started shipping to the U.S. and Canada in February.