CAMBRIDGE, MA — Asia, Africa and the Middle East will lead online growth for the next five years while the industrialized West slows to a crawl, according to a new report from Forrester Research.In 2008, the top five countries in terms of numbers of internet users were the U.S., China, Japan, Brazil and Germany, in that order. By 2013, demographics will shift. The list is expected to become China, the U.S., India, Japan and Brazil.

Worldwide, the global online population will grow more than 45-percent to 2.2 billion users by 2013, according to the report. Asia remains the biggest growth engine: 43-percent of the world’s online population will reside in Asia by 2013, with 17-percent of the global online population in China.

Conversely, growth rates in the U.S., Western Europe, and the major industrialized nations in Asia Pacific such as Australia, Japan and South Korea will slow to between 1 percent and 3 percent.

Online penetration in the U.S. is set to rise from 73-percent to 82-percent over the next five years, representing about a 3-percent annual growth rate. By 2013, U.S. online penetration will be on par with the most highly penetrated markets of Europe and Asia, such as the Netherlands, the UK, Japan, and South Korea.

Europe’s internet growth will be fueled by the continent’s emerging markets. Internet usage in Russia and Turkey will grow by almost 8-percent annually, while growth in Spain’s online population will increase by an average of more than 5-percent each year.

China’s online population — already the largest in the world — will rise by nearly 11-percent each year over the next half decade. Other Asian countries with substantial online growth rates include India, Indonesia, Pakistan and the Philippines. By contrast, growth rates in some of the more mature markets such as Japan and South Korea will rise by less than 2-percent each year.

Brazil, currently the fourth largest market in the world in terms of number of internet users, is expected to drop to the No. 5 position in 2010 and stay there, despite a 7-percent annual growth rate over the next five years. India will take Brazil’s place in the global hierarchy.

The countries of the Middle East and Africa currently represent just 8-percent of the global online population but over the next five years will see some of the highest growth rates in the world: around 13-percent. Egypt, Iran and Nigeria are among the countries with the highest growth rates in the region.

“While per capita online spending is likely to remain highest in North America, Western Europe and the developed markets of Asia throughout the next five years, the shifting online population and growing spending power among Asian consumers means that Asian markets will represent a far greater percentage of the total in 2013 than they do today,” Forrester Research Senior Analyst Zia Daniell Wigder said. “Multinational organizations must understand the dynamics of the shifting global online population to ensure that they are positioned to take advantage of emerging international opportunities.”