A few years back I worked with two engineers who sat side by side, over the course of a month the one girl fixed one bug, while the guy next to him did 22. Having worked with them both I believe they were actually about equal despite the numbers. The girl randomly drew a complex bug that was hard to figure out, while the guy got a bunch of easy ones (including one the is not spelled t-e-h)

This variance is why it is so hard to assign objective numbers.

>number of bugs

Bugs are not created equally.

So anyone who puts in lots of bugs in the first place, will look great in the numbers, because they were so great at fixing all those bugs.