Boeing Commercial Airplanes reported its lowest quarterly passenger jetliner delivery count in three years.

Boeing (NYSE: BA) said Thursday it made 169 deliveries during January, February and March of this year.

That’s down from the 176 it turned over to airline customers during the first quarter of 2016. Boeing delivered 184 commercial aircraft in the first quarter of 2015.

The biggest factor was a drop in the number of its 737 Next Generation passenger jet deliveries as Boeing workers focused…