Could someone please explain Group XP bonuses and penalties

[Auuken]

I'm wondering how EXP is divided when grouping with 2, 3, .. full 6 members.

Is there an XP bonus for full group?

Is it just an even split? such as 2 players = 50% of the exp per kill, 3 players = 33.33% of exp per kill and so on?

It honestly seems like the amount of exp i get for a solo kill isn't much less than the exp I get for a group of 6 kill. Seems like 75% of a solo kill at least.

Does anyone know how it works?

Thanks