I'm not sure how useful it would be- you'd also really need to know how far each user was from the cabinet (to get an average/spread), and the most important datum (number of connected users) isn't easy to find on a regular basis. OpenReach will presumably know, but I'm sure we've all tried getting information out of them
You'd also need to know whether each user was on 40Mbps or 80Mbps... eg I'm quite sure that if I dropped back to a 40/10 product my reaction would be "Crosstalk? What crosstalk?"
So you'd end up with two 4-dimensional tables, one for 40Mbps users, another for 80Mbps, each having:
Speed loss due to crosstalk
Distance from cabinet
No of connected users
Proportion of 80/40 users