Cruise ship tours are reportedly becoming a boom industry out of China, with the number of cruise passengers from China rising tenfold in the last 5 years to some 2 million people in 2016, reports Bloomberg.

Those numbers are expected to reach 4.5 million by 2020, the article explains.

Most Chinese passengers prefer to make shorter trips, 5 days on average, with South Korea and Japan being the top two overseas destinations, according to industry body Cruise Lines International Association.

China, the world's fastest-growing cruise market, has attracted international lines including Royal Caribbean Cruises and Carnival Corp. to China. But Bloomberg is reporting the international lines face challenges from Chinese firms hoping to tap the cruise line sector.

Different from other cruise passengers, the Bloomberg report notes that Chinese passengers prefer to shop on the cruise ship, and spend two to three times more on the actual cruise ship itself, rather than at ports-of-call. The Bloomberg report also says that Chinese passengers prefer to travel with their family members.