The investment volume in China’s tourism market exceeded 1 trillion yuan ($151.5 billion) last year, with turnover totaling 4.69 trillion yuan.

However, there was still huge room for further growth as online tourism becomes increasingly popular among consumers and investors, a report said.

According to the 2016 China Tourism Investment Report, online tourism contributed 100 billion yuan to the total investment, and the combination of tourism plus the internet will create new opportunities for the market.

“In four years, Alitrip’s revenue grew 15-fold to 100 billion yuan in 2016, the fourth largest in online traveling sector globally. We believe the Chinese online traveling market is big enough to have companies reaching the trillion yuan mark,” said Zhou Zheng, vice-president of Alitrip.

Alitrip, the online travel affiliate of Alibaba Group, made the achievement with less than 1,000 employees thanks to automation and intelligent technologies. “Traditional online business operators need ten folds of employees, but we can do the same thing with less staff,” said Zhou, adding that consumer experience is still their top priority.

Sun Jie, CEO of Ctrip, China’s largest online travel platform, reported 350 billion yuan in transaction volume in 2015.

Sun made a similar projection that Ctrip’s sales revenue will reach 1 trillion yuan by 2018, and further expand to 2 trillion yuan in 2021.

The internet has changed the landscape of the tourism industry and made it become a global economic engine. In 2016, the tourism industry posted $7.61 trillion in revenue, accounting for 10.3 percent of the world’s GDP, according to data from Pintu Insitute.

In China, the online tourism market surpassed 600 billion yuan in 2016, growing 34.3 percent year-on-year.