As a researcher, I am very happy that recently all the conferences and journals we usually publish to champion open access publishing. Due to this, all my work is currently FOSS and all the papers open access. That is a great change to the papers of the past where you have to have an affiliation to a university to get access to a paper and sometimes even that is not enough.

I especially appreciate that the graph is designed as “Linux” and “Other” instead of “Windows”, maybe “MacOS” and “Other”.

You are mistaking KMail (desktop client by KDE) and K-9 Mail (Android client that is being rebranded into Thunderbird for Android).