Apple Inc posted another record quarterly revenue on Wednesday, but the United States tech giant seems to have lost the momentum in smartphones, which generates nearly 70 percent of its revenue.

A slower economy and the already-high handset penetration rate in China may soon prompt Apple to seek new growth drivers, industry sources said.

The Cupertino, California-based company said growth in iPhone sales reached the slowest point since the late Apple co-founder Steve Jobs launched the product line in 2007. Apple shipped 74 million iPhones in the quarter ended in December 2015, an increase of 300,000 units year-on-year.