Hyphen in part-time

This Monday i give my first lecture for a class, lol. I'm interested how native spell part-time? Books say part-time when an adjective (I'm a part-time student, this is a part-time job) but i often see that people use as adjective without hyphen (I'm a part time student) does it depend on British/American? Or anyway it should be with hyphen, but people just drop hyphen for simplicity? How is it in your place?