I recorded profession distribution from 10 games (not counting myself) of unranked/amber/emerald/sapphire.
necromancer 26% (23)
ranger 15% (13)
elementalist 13% (11)
mesmer 13% (11)
thief 10% (9)
guardian 8% (7)
engineer 8% (7)
revenant 5% (4)
warrior 3% (3)
Except for necromancers and maybe warriors and revenants, it’s a uniform distribution. I haven’t seen other threads with class distribution, except for pro leagues.