Wikipedias, participation per language (= active editors per million speakers) https://stats.wikimedia.org/wikimedia/participation/d3_participation_global.html
Breakdown by continent https://stats.wikimedia.org/wikimedia/participation/d3_participation_continent.html
@e8johan The circles represent editors per number of speakers. In any case, you can ask at https://lists.wikimedia.org/pipermail/wiki-research-l/2018-September/006390.html
@quimgil do you have another one where the circles are editors per number of speakers? It would be interesting to see.