SHANGHAI  China said the number of Internet users in the country reached about 253 million last month, putting it ahead of the United States as the world’s biggest Internet market.

The estimate, based on a national phone survey and released on Thursday by the China Internet Network Information Center in Beijing, showed a powerful surge in Internet adoption in this country over the last few years, particularly among teenagers.

The number of Internet users jumped more than 50 percent, or by about 90 million people, during the last year, said the center, which operates under the government-controlled Chinese Academy of Sciences. The new estimate represents only about 19 percent of China’s population, underscoring the potential for growth.

By contrast, about 220 million Americans are online, or 70 percent of the population, according to the Nielsen Company. Japan and South Korea have similarly high percentages.