Of the 781 million games installed on Steam since Valve's client launched in 2004, 37 per cent have never been played according to Ars Technica.
A further 17 per cent of games have only been played for under an hour although it's important to note that the hours played metric was only introduced in March, 2009 meaning older games are likely to show far less accurate overall playtime than newer titles.
Many Steam games are included in packaged deals or given away in competitions while some of the most popular are free to download. Even so, research done on 85,000 Steam accounts for each test performed show that only half of installed games have been meaningfully engaged with.
Dota 2 is the most popular Steam game having been installed almost 26 million times followed by Team Fortress 2 which stands at over 20 million played installations. Half-Life 2 comes third with 12.8 million played installations and The Elder Scrolls 5: Skyrim has been downloaded six million times.
Dota 2 is also by the far the game with the most playtime – 3,828 billion hours – while Team Fortress 2 stands at 1,444 billion hours of game time.
Also revealed are the most unplayed games on the system with Valve's Ricochet played by just 300,000 of the title's 6.7 million owners. Half-Life 2 Lost Coast expansion has been used by 2.1 million players despite being on 12.8 million accounts.
Perhaps surprisingly, the most played gamer per head is Sport Interative's Football Manager 2014 which has racked up 100 hours for every player, nearly double the 53 hours spent by most Skyrim players.
Steam has 75 million active users and reached seven million concurrent users in December.