China's uncertain economic landscape apparently has not dampened Apple's sales in the country, where the iPhone maker posted an 84 percent increase in sales.

For its fiscal year, ended September 26, Apple clocked US$23 billion in operating income for the Great China region, including Taiwan and Hong Kong, more than doubling its US$11.03 billion profit last year. Its operating margins for the region climbed 39 percent, compared to 35 percent last year and 31 percent in 2013, reported The Wall Street Journal.

Revenue for the year increased by US$27 billion in Greater China, where it remained unaffected by the country's economic slowdown, Apple CEO Tim Cook said in the report. China alone accounted for 96 percent of sales in Greater China, the company said.

Cook in 2013 said he expected the Chinese market to become the company's largest in the future and it was focused on localising products to meet the needs of local consumers.

Apple operates 25 stores in China, which is currently its second-largest market, and is planning to grow this number to 40 by mid-2016.

For its fiscal fourth quarter, the Greater China region clocked US$12.52 billion in revenue, dipping 5 percent from the previous quarter but growing 99 percent from the same quarter last year. Apple's total global revenue for the quarter was US$51.5 billion, with the Americas accounting for US$21.78 billion. Worldwide, the device maker said it sold 48.04 million iPhone units.

According to IDC's preliminary third-quarter 2015 numbers, however, Apple still sold fewer handsets globally than arch rival Samsung. The Korean handset manufacturer retained its pole position with 84.5 million units shipped, representing a 6.1 percent increase from 2014.

The market researcher said Samsung stuck to its focus on premium handsets with the launch of two new flagship devices, the Galaxy S6 edge + and Note 5. "Beating Apple to the punch with an untraditional August launch for the Note series, and new S6 edge+, Samsung saw stronger than normal September shipments as the new iPhone was yet to be released. Outside of the key flagship models, sub-US$200 devices [including] Galaxy Core/Grand Prime, and J-Series drove a majority of shipments in many key emerging markets," it added.

IDC's program director for its worldwide quarterly mobile phone tracker, Ryan Reith, noted: "The vendor landscape and product offerings are really unique at the moment as many markets are seeing consumers become more aware of alternative buying options when it comes to paying for their smartphone.

"In mature and subsidised markets, we now have a wide range of operators offering equipment installation plans, as well as early trade-in options. At the same time the number of unlocked or off-contract offerings has increased significantly and it's slowly starting to resonate with consumers," Reith explained. "Within these markets these moves will put pressure directly on Android OEMs with offerings that are greater than US$500."

IDC, however, said the majority of shipment volume and growth would come from low- to mid-range handsets, especially in emerging markets.

For the quarter, Samsung grabbed 23.8 percent share of the global smartphone market, followed by Apple's 13.5 percent and Huawei at 7.5 percent.