Attending Haileybury costs up to $28,000 a year.

TIANJIN, China (AP) — The school year at Haileybury College's campus outside Beijing began with three People's Liberation Army soldiers marching on a running track as the Chinese national anthem played over loudspeakers. Seven hundred students stood silently in single-file lines, their hands crossed, the international prep school's crest emblazoned on many of their coats and T-shirts.

Attending Haileybury costs up to $28,000 a year. But Haileybury, which opened the Chinese version of its century-old Australian prep school three years ago, nearly doubled its enrollment this year and is considering opening a second campus in China.

Getting into China's best public high schools can be monumentally difficult, but regardless of whether their child has the academic chops, many parents are opting to pay for what they see as a less stressful and more enriching experience at an international school.

The International School Consultancy, which monitors school trends worldwide, says the demand among Chinese for English-language schools like Haileybury is "insatiable." More than 150,000 Chinese students are currently enrolled in international schools, according to the consultancy, which says the number of Chinese who can afford to pay seemingly stratospheric fees for those schools — even if it's just a small percentage of the country's population — will continue to grow, absent a dramatic downturn in China's economy.

Once limited mainly to foreign children, international schools have been allowed during the last two decades to open campuses for Chinese students jointly with local companies. And while the Chinese government has sought to tighten its ideological control over textbooks and limit perceived Western influences, the international schools offer a valuable infusion of new teaching methods and options for China's middle class.

That opening has brought in some of the world's biggest brand names, joining long-established international schools in Beijing and Shanghai. Britain's Dulwich College now runs schools for Chinese students in the eastern city of Suzhou and the southern city of Zhuhai; Britain's Hurtwood House operates in association with a school in eastern Ningbo.

While China's economic boom has allowed millions of families to afford options like Haileybury, international schools remain out of reach for the vast majority of Chinese. Zeng Xiaodong, a professor at Beijing Normal University, said she understood that parents who could afford those schools were seeking a pathway for their children "to understand the future and be a member of the international world." But those options remain closed to rural families and don't solve the inequity of the overall system, she said.

Wang, the University of Hong Kong professor, said China's overall system may eventually benefit from the introduction of new teaching methods by international schools. But for now, particularly in rural areas, poor and even many middle-class children don't have access to better teaching, while upper-middle-class children are increasingly learning in a separate system.

"The inequality of China right now is really dividing the population, and each group is playing a different game," she said.

Associated Press videojournalist Thomas Suen and researcher Yu Bing contributed to this report.