Wow meters online provides a useful comparison of the average top fifty performers from each class in their data bank, for each boss.
World of logs lists the top individual performers for each raid boss.
Elitist Jerks theorycrafts max dps by class and spec.
All of them indicate that retribution is performing poorly. I am aware of no data that suggests otherwise, but if it is out there I would dearly like to see it.
I suggest that the class needs further work. I fear us being seen as lolret again.