Valve has published a sort of list to promote the top 100 grossing games on their distribution service, Steam, last year, and it shows how titles older than 2016 are just as good earners.
The list isn't ranking each game, but is instead divided into different categories. The top grossing games are in the Platinum, the next is Gold and so on. In the Platinum category we find a 50-50 mix of 2016 releases and older games, spanning from The Division and Dark Souls III to Dota 2 and Grand Theft Auto V. Another thing to note is that strategy games are very strong on Steam with three titles in the Platinum category and plenty more in the full top 100. Free-to-play titles also seem to be doing well on the platform (Dota 2 in particular), even if paid games are still Steam's bread and butter.
Check out the list on the link above, and tell us which titles you spent your money on (in) last year.