Apple iOS is the fastest growing mobile operating system in 2013, with iPhone users growing from 14 per cent of worldwide market share in Q1, 2013 to 19 per cent in Q3, according to GlobalWebIndex.
The research, based on 89 per cent of the global Internet population, found the number of iPhone users is expected to grow to 233 million this year, with iPads users estimated at 165.72 million.
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iOS may be the fastest growing mobile operating system, but Android is still dominating the market, with a 57 per cent share. GlobalWebIndex estimates Android users will total 708 million this year.
The research firm also predicts Android will be the world's number one mobile operating system by early 2015.
Windows Phone users are estimated to total 68.26 million this year, surpassing BlackBerry at 62.56 million.
Turning to PCs, the research firm found that the Windows 7 operating system takes the lead at an estimated 734.12 million users this year, with Windows 8 users coming under at 168.11 million. Meanwhile, there will be an estimated 47.78 million Apple Mac users this year, the research firm said.