Group xp increase, and mercs don't take as much as i thought?

I've heard that:

"Player characters now give extra exp in a group; mercs count the same as players used to (so group exp still increases with mercs, just not as much)."

Confirm, deny? Anyone know the actual % levels? I know players in group used to give:

2-20% bonus
3-40%
4-60%
5-80%
6-same split as 5. effectively 116%

Divide the value of the mob by the number in the group. Examples, base mob 100% value killed solo, killed by 2 in grp mobs value is 120% by 2 for 60 % value each-- mob killed by 3 in group, 140% by 3 or 47 % value each. Since it would be expected that 3 can kill more then twice as fast as one, while each gets less per kill, the count would go up, and risks of death should go down, enhancing the experience overall. There are caveats, regarding level range in the group, AA value based off highest level char in group.

The percentages given are close enough, and were set during PoP, but don't include the player character bonuses added not so very long ago; I don't know how much extra those are. The PoP bonus work for mercs as well as player characters.

If you are playing solo, you get 100% of mob kills. With a single merc, each kill is 119%, but divided by two (for the group), so you basically get 60% of each kill. If the merc is speeding up your kill rate, that's great - but if they are just there for comfort and joy, you are losing 40% of your exp.

What Borek-VS said. I do not think the Dev's ever gave us any hard numbers for the PC over Merc bonuses added in the last few years. Let alone a break down at each group size & PC vs Merc combination.

I also read that the group xp bonus increased beyond the 20/40/60/80% level, was one of the most recent expansions (HoT?) that implemented this. Mercs now count as a player and provide the old 20/40/60/80% bonus.

I remember patch notes confirming the post title.
Something along the lines of "xp per player increased, mercs give a lower bonus"
I also remember seeing some hard factual numbers but I wouldn't even know where to begin looking these up.