China's Internet users totalled 538 million at the end of June, with mobile phones become the most popular way for users to access the Internet, according to a non-profit research group in the country.
The new figure, which comes from the government-linked China Internet Network Information Center (CNNIC), means Internet penetration in the country is at 39.9 percent. In contrast, the U.S. has 77.3 percent Internet penetration rate, according to Internet World Stats.
In this past six months, China added only 24.5 million new Internet users, the lowest level of half-year growth the country has seen for at least the last four years. In CNNIC's report, the group pointed to the maturing of the country's Internet market, where access is widely available in China's better developed urban areas.
To increase Internet penetration further, the nation will have to target citizens with lower education levels, along with people living in less developed areas of the country. In a survey of people who do not use the Internet, the CNNIC found that 54.8 percent of respondents did not use it because of "not understanding computers or the Internet."
Despite the slowdown in growth, the CNNIC said mobile phones, and their declining cost, could help bring more of China's citizens into its Internet population.
The number of China's mobile Internet users has reached 388 million, up from 33 million six months ago. The figure, for the first time, exceeded the total number of users who access the Internet via desktop computers, which has reached 380 million. Experts have attributed this to the rise of low-cost smartphones in the country, which are often priced at around $150 without signing a carrier contract.
CNNIC's stats, however, measure Internet users as persons aged 6 and up who have used the Internet in the past six months. This has caused some experts to call CNNIC's figures inflated.
In CNNIC's report, the top five Internet services used in the country include instant messaging, search engines, online music, news and blogs. About half of the country's users frequent Twitter-like microblogging sites, which have come under heavy scrutiny from authorities over recent months for being forums to voice negative opinions of the government.