I am looking towards concentration saves, and getting to +9 means automatic success on a low damage check, or a check up to 21 damage.
At some point I assume the average single hit may exceed 21, which would necessitate a higher CON save, but I am not sure when that would be.
So, using creatures from the monster manual only if that helps (although all creatures may be more useful) what CR am I likely to be facing when a single hit will cause more than 21 damage on average?
By average I mean something like "the average CR5 monster does x damage on a single hit". I am also not considering the source of the damage, a spell, melee attack, breath weapon etc all count (although spells and breath weapons could take into account save chances to determine average damage, and I will be a Paladin with +5 to everything at least by level 6).
To provide a bit more clarity after a comment, I am not worried about critical hits, and I am assuming I actually get hit, so hit chance isn't a factor, just the damage a hit would cause.
I know there are a lot of people here who dislike "average" questions, but please don't ask me if this is an x/y question, and don't comment that averages aren't useful. They are useful to me and I can use this to decide at what level (and if) I need the Resilient Constitution feat.
I haven't found the monster creation tables useful, because that is damage per round, and my next step would probably be checking all the creatures manually, but this may be community knowledge somewhere.

