Chinese airlines are likely to buy more than 7,000 planes worth $1.1 trillion (844.6 billion pounds) over the next 20 years, as they grow their fleets to meet robust demand for domestic and international travel, Boeing Co said in a bullish forecast on Wednesday.

Its latest estimate of 7,240 aircraft purchases for the period to 2036 is 6.3 percent higher than the U.S. planemaker’s previous prediction of 6,810 planes last year.

“China’s continuous economic growth, significant investment in infrastructure, growing middle-class and evolving airline business models support this long-term outlook,” Randy Tinseth, Boeing Commercial Airplanes vice president of marketing, said.

“China’s fleet size is expected to grow at a pace well above the world average, and almost 20 percent of global new airplane demand will be from airlines based in China,” Tinseth said in a statement.