All Players Per Game
Estimated number of all players for Steam games with multiple achievements.
Calculated by finding the lowest number of players that produces whole numbers of players for each achievement (percent achieved * all players).
All players is different from owners or unit sales. For popular non-discounted games, players may be over 90% of owners, but for discounted games, players may be as low as a few percent of owners.
This chart was inspired by Steamspy and the search for another estimation method after Steam changed the privacy setting default to friends-only. This article by Jake Birkett showed how the number of reviews provides a range, which is a useful sanity check. Finally, this article by Tyler Glaiel avoided error tolerances and worked for games with 10M+ players.
Due to API changes, the last player count update was on July 3.