The total number of PCs in use today has broken the one billion mark, according to new figures from Gartner.

The analyst house has calculated that the installed base of PCs grows by around 12 per cent a year. If this continues the number of systems will reach two billion by 2014.

"Whereas mature markets accounted for just under 60 per cent of the first billion installed PCs, we expect emerging markets to account for approximately 70 per cent of the next billion installed PCs," said Luis Anavitarte, research vice president at Gartner.

"Emerging market governments are also increasingly committed to reducing the digital divide by promoting PC use among their citizens through a variety of means, including providing PCs directly to the less affluent."

Geographically mature markets in the US, Europe and Japan contain just 15 per cent of the world's population but account for 58 per cent of the installed base of PCs.

However, while falling prices and better wireless communication will drive adoption in developing markets, this is coming at a price to the environment as not enough PCs are being recycled.

"We forecast that just over 180 million PCs, approximately 16 per cent of the existing installed base, will be replaced this year," said Meike Escherich, principal research analyst at Gartner.

"We estimate that a fifth of these, or some 35 million PCs, will be dumped into landfill with little or no regard for their toxic content.

"It will become an even more pressing issue, especially in emerging markets, as the number of retired PCs grows with the continuing expansion of the PC installed base."