My favorite application to do this is git-quick-stats[0]. Then just multiply by something value (maybe 7/4.8) to calculate an estimate of the number per workday. For me, it appears to be roughly 500 lines per day. However, this is just a side project I work on in my spare time. This is a mean though, not a median (which would probably be more fitting), so should definitely be taken with a pinch of salt.

[0] https://github.com/arzzen/git-quick-stats