The number of installed PCs worldwide has surpassed 1 billion units, according to Gartner, Inc. Gartner analysts estimate the worldwide installed base of PCs is growing just under 12 percent 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 percent of the world?s installed PCs, but these markets only account for 15 percent of the world?s population," said George Shiffler, research director at Gartner. "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."

"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."

"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," said Luis Anavitarte, research vice president at Gartner. "Whereas mature markets accounted for just under 60 percent of the first billion installed PCs, we expect emerging markets to account for approximately 70 percent 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 percent of the existing installed base ? will be replaced this year," said Meike Escherich, principal research analyst at Gartner. "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."

Analysts will provide more detailed analysis on the state of the PC industry, as well as analysis on server and printer markets, during the Gartner Hardware Briefing June 25 at the Gartner U.K. headquarters in Egham.