Alaska Airlines has placed an order for six Boeing 737-900ERs in a deal valued at $594 million at list prices, the Seattle-based carrier announces.

Four of the aircraft are scheduled to be delivered in 2016 and the remaining two are scheduled to join Alaska’s fleet in 2017, says the carrier.

The orders will bring to 79 the number of 737s Alaska will have following the deliveries; the carrier now expect to take delivery of a total of 19 aircraft next year.

Alaska, a subsidiary of Alaska Air Group, currently has 21 737-400s, 14 737-700s, 61 737-800s, 12 737-900s and 23 737-900ERs, according to the Ascend Fleets database.

The carrier also has a fleet of six 737 freighters or passenger-freighter combos.

Source: Cirium Dashboard