The number of installed PCs worldwide has surpassed 1 billion units, according to Gartner market tracking firm. Gartner analysts estimate the worldwide installed base of PCs is growing just under 12% annually. At that pace, it will surpass 2 billion units by early 2014.

Gartner defines the installed base of PCs as the estimated number of PCs in use as opposed to the number shipped over a given a period, which is reported in Gartner’s PC forecast and market share reports. The world’s installed base of PCs remains heavily concentrated in mature markets. However, emerging markets will claim an increasingly larger share of the world’s installed base going forward as the rapidly rising PC penetration in emerging markets continues to drive strong double-digit PC growth.

 “Mature markets such as the United States, 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,” said George Shiffler, research director at Gartner.

As of June 21, 2008, the world’s population is believed to be 6.7 billion, which means that virtually only one human out of seven has access to a PC

“There’s a startling difference in per capita PC penetration between mature and emerging markets. Of course, much of this difference reflects the disparity in average living standards between mature and emerging markets. But, rapid economic development across emerging markets is not only narrowing the disparity in average living standards, it's closing the difference in per capita PC penetration between mature and emerging markets,” said Mr. Shiffler

“We expect per capita PC penetration in emerging markets to double by 2013,” added Mr. Shiffler. “Rapid penetration in emerging markets is being driven by the explosive expansion of broadband and wireless connectivity in these markets, the continuing fall in PC average selling prices (ASPs), and the general realization that PCs are an indispensable tool for advancement.”

Luis Anavitarte, research vice president at Gartner, expects  emerging markets to account for approximately 70% of the next billion installed PCs.

The global PC installed base is constantly being churned as PC users replace their used machines with new ones. Some retired PCs find their way back into the installed base to second owners through various channels, some are broken up and recycled, but others are simply dumped directly into landfill.

“We forecast just over 180 million PCs – approximately 16% of the existing installed base – will be replaced this year. We estimate a fifth of these, or some 35 million PCs, will be dumped into landfill with little or no regard for their toxic content. The disposition of retired PCs has become a high-profile issue for many PC vendors, governments and environmental interest groups. 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,” said Meike Escherich, principal research analyst at Gartner.