Hijacking this question to talk a bit about Jolla and open source.

I don't have metrics for everything, but here's what I do know.

The central focus of Jolla's open source efforts are in the Mer and Nemo environments, because those are where we get the basis for our distribution (Sailfish OS). These are open projects and not just run by any one individual or organisation, but we contribute quite a good slice. A large part of our work is based on and around open source software.

You can follow through the individual projects where much of this work happens:
https://github.com/mer-packages/
https://github.com/nemomobile-packages/
https://github.com/nemomobile/

Onto some metrics:

https://www.ohloh.net/p/nemomobile

(note the dip in 2012 when Nokia ceased their activities, and note how it's been steadily increasing since - again, not everyone in Nemo is working for Jolla - but there's quite a number of us)

Jolla also contributes to other projects, such as my own personal favorite - Qt:

http://www.macieira.org/~thiago/qt-s...r.absolute.png