Apple Inc.'s iPhone sales slump in China is deepening and the company is likely to see volumes decline further this year, according to Jefferies analysts led by Edison Lee. The iPhone maker's latest generation, iPhone 15, got off to an atypically sluggish start in China last year, which most recently expanded to a 30% year-on-year decline, Lee and colleagues said in a note on Sunday, citing industry checks. The rest of the country's mobile market grew in December, with Huawei Technologies Co. growing fastest on the back of its new Mate 60 device lineup.