The global industry group GSM Association (GSMA) said the number will increase to six billion by 2013, according to a Reuters report.
GSMA notes that the figure does not mean we have 4 billion users across the globe as many users own several handsets.
Quoting a GSMA official, Reuters said that a fifth of Western Europe mobile phone users use more than one device. Meanwhile, in poor countries, phones are usually shared.
GSMA also claims that of the 4 billion, about 100 million were "mobile broadband" connections, referring to mobile internet connections using high-speed HSPA standards.


