BEIJING, Sept. 13 (Xinhua) -- China is expected to demand 200 new air-cargo freighters and 470 converted freighters over the next 20 years, said a senior official of Boeing in Beijing.

"Demand for air-cargo freighters is expected to expand exponentially thanks to China owning the world's fastest growing e-commerce industry," said Randy Tinseth, vice president of commercial marketing for the Boeing Company.

Boeing forecasts that the fleet of China's air-cargo freighters will expand from about 180 in 2017 to 740 by 2037.

In Tinseth's point of view, China's e-commerce market has the highest trading scale in the world, giving China's cargo transportation market enormous developmental potential.

Over the past decades, mass transportation of goods is the major source of China's air cargo industry. And the emerging e-commerce, featuring in massive loose goods from scattering online stores, gradually change the source, structure as well as the volume of China's air cargo goods.

Even until eight years ago, the market size of e-commerce in China was only about half of that in the United States. And now, its market size in China is twice over in the United States, according to Tinseth.

Over the past five years, Boeing freighters' orders and deliveries account for more than 90 percent of the total global market, he said.

In 2016, Boeing launched the 737-800 Boeing Converted Freighter program here in China, and the first 737-800BCF has been delivered to the buyer.

China has seen a robust air express industry. In 2017, China transported 7.06 million tonnes of airmail cargo, a 5.6 percent increase year on year, according to statistics from the Civil Aviation Administration of China (CAAC).

"We feel a large amount of enthusiasm from our customers in the air cargo business and are confident in continuously supporting their growth in the dynamic market in China," said Tinseth.