Update: GM spicycaterpillar is now the sole leader in the all time rankings, and his impressive average score is clearly not a target at all, since he has several single digit scores in the last 25 (due to solving puzzles at 1 second to 2 seconds each and being a bit unfortunate.!
Mostly, people seem interested in their best score at Puzzle Rush, which is interesting but often a rare statistical outlier. An alternative viewpoint is to try to be consistent in your scores, by avoiding low scores.
I thought I was quite consistent with an average just over 75% of my best, but how about this?
https://www.chess.com/member/gothgirlgames
Average puzzle rush score 85.5% of best (pretty good best too) - 31.78 / 36 .
The equal top of the all time rankings has managed it while being pretty consistent too, with an average of 39.81 for a best of 55.