Boeing said on Tuesday that it delivered 57 jets in September, up from 51 in August and 55 a year earlier as it works to ramp up production of its best-selling 737 MAX narrow-body. It was the planemaker’s highest monthly total so far this year.

Turkish Airlines’ order for 100 737 MAX jets boosted Boeing’s September total of new orders to 165.

The US planemaker still trailed European rival Airbus’ 72 deliveries in September, but Boeing far outsold its rival, which booked only 17 new orders from two customers last month.

• Boeing’s September deliveries included 43 737 MAX jets, eight 787s, two 777 freighters and four 767s, including three for Boeing’s defense unit for completion as KC-46 aerial refueling tankers.

• The higher deliveries come as Boeing works to consistently increase 737 MAX output to 47 jets a month, which has taken longer than expected, Boeing CEO Kelly Ortberg said during an investor conference in September.

• Through September, Boeing has delivered 475 jets this year, up 8% from a year earlier. That includes 363 737 MAX jets, the most the MAX program has ever delivered in the first nine months of a year.

• In addition to Turkish Airlines’ order, Boeing booked orders for 20 737 MAX jets for Lufthansa, six 737 MAX and five 787 jets for Biman Bangladesh Airlines, and eight 777-8 freighters and two 777 freighters for Ethiopian Airlines. Another six 737 MAX and 18 787 orders came from unidentified customers.

• Boeing ended September with an official backlog of 6,371 jets, up from 6,156 at the end of August.

(Reporting by Dan Catchpole in Seattle; Editing by Jamie Freed)