Steam stats show that the number of concurrent logged in users has now exceeded 20 million. The all time highest number for Steam at the time of writing is now 20.3 million users which ocurred on Sunday March 15th, 2020.
This comes as no surprise as lockdowns continue to be announced worldwide with more and more people staying at home due to Covid-19. Not only this, but the Steam userbase continues to grow, and certain Steam games like CS:GO also achieved its all-time concurrent player peak of over 1 million this Sunday.