Worldwide sales of mobile phones to end users reached 419.1 million units in the first quarter of 2012, a 2% decline from the first quarter of 2011, according to the latest data from the Gartner research group (http://www.gartner.com). The data also shows that, although Apple only sells smartphones, it represents almost 8% of all worldwide mobile phone sales, making it the third-largest handset maker.

“Global sales of mobile devices declined more than expected due to a slowdown in demand from the Asia/Pacific region,” says Anshul Gupta, principal research analyst at Gartner. “The first quarter, traditionally the strongest quarter for Asia, which is driven by Chinese New Year, saw a lack of new product launches from leading manufacturers, and users delayed upgrades in the hope of better smartphone deals arriving later in the year.”

Samsung became the world’s top mobile handset vendor during the quarter, displacing Nokia which had held the No. 1 spot since 1998. Samsung’s mobile phone sales reached 86.6 million units, a 25.9% increase from last year. Samsung took back the world’s No. 1 smartphone position from Apple, selling 38 million smartphones worldwide. In addition, Samsung’s Android-based smartphone sales in the first quarter of 2012 represented more than 40% of Android-based smartphone sales worldwide; no other vendors achieved more than a 10% share of the market.

Sales of smartphones continued to drive mobile device market growth, reaching 144.4 million units in the first quarter of 2012, up 44.7% year-over-year. This quarter also saw the top two smartphone vendors, Apple and Samsung, raising their combined share to 49.3%, up from 29.3% in the first quarter of 2011, and widening their lead over Nokia –which saw its smartphone market share drop to 9.2%.

Driven by the continued success of the iPhone 4S, Apple’s sales grew 96.2% in the first quarter of 2012 as the new model expanded into new markets and carriers. Sales in China were particularly strong this quarter. With more than five million units, China became the second-largest market for Apple after the U.S. On top of the sales through official carriers’ channels, there was an increase in transshipments from Hong Kong where volume has been growing over the past few quarters to reach a sell-in of more than three million units.

RIM sold 9.9 million mobile handsets in the first quarter of 2012, with its global share declining to 2.4% as competition increased in its international market strongholds.

In the smartphone OS market, Android accounted for more than half of all smartphone sales (56.1%) in the first quarter of 2012. Gartner analysts said the smartphone market has become highly commoditized and differentiation is becoming a challenge for manufacturers.