The number of Apple devices in use around the world has topped 2.5 billion. (AFP pic)SAN FRANCISCO : Apple on Thursday said it saw record-high earnings in the final three months of last year, with iPhone sales surging in greater China. “iPhone had its best-ever quarter driven by unprecedented demand,” chief executive Tim Cook said in an earnings release. The number of Apple devices in use around the world has topped 2.5 billion, Apple reported. In December, it announced that the head of its artificial intelligence team was stepping down.