The number of installed PCs worldwide has surpassed 1 billion and will reach 2 billion by early 2014, if the present 12% annual growth rate continues, according to Gartner Research.

The installed base of PCs is the estimated number of PCs in use as opposed to the number shipped over a given a period.

The world's installed base of PCs remains heavily concentrated in mature markets.

“Mature markets such as the U.S., Western Europe and Japan currently account for 58% of the world's installed PCs, but these markets only account for 15% of the world's population,” says George Shiffler, Gartner's research director.

However, emerging markets will claim an increasingly larger share of the world's installed base going forward.

Shiffler says rapid penetration in emerging markets is being driven by the explosive expansion of broadband and wireless connectivity in these markets and the continuing fall in PC prices.