A year of robust travel demand and strengthening yuan helped annual profits at China Southern Airlines rise by 17% to a record high.

China’s largest carrier by passenger numbers saw net profit in 2017 reach 5.91 billion yuan ($941 million).

China Southern Airlines’ previous best-ever net income result was 5.8 billion yuan in 2010.

Revenue rose 11% to 127.5 billion yuan over 2016 and the airline achieved 1.79 billion yuan in foreign exchange gains as the Chinese currency has appreciated about 10% against the US dollar since the start of 2017.

The weakened dollar has helped slash the financing expenses of China Southern as well as rivals Air China and China Eastern Airlines, which used dollar-denominated loans to expand fleets, Reuters reported

China Southern said its passenger yield fell 2% while capacity on domestic and international routes grew by 9.63%.

American Airlines last year acquired $200 million worth of China Southern shares, the first step in a planned “long-term relationship” between the two.

Air China is expected to report its biggest profit since 2010, and China Eastern Airlines is forecast to deliver its best result since at least 1996.