Valve's Counter-Strike: Global Offensive went free-to-play in the beginning of last month, also receiving a new battle royale mode called Danger Zone, and both of these factors might have played important roles in growing the game, as PCGamesN reports that last month saw the highest amount of unique players recorded, doubling figures from November.
These numbers come from CS:GO observer Nors3 on Twitter, who revealed that December saw 20,535,709 unique players come to CS:GO, which is actually "the biggest number ever recorded for Counter-Strike."
Steam Charts tracks average and peak concurrent players, and here we see that in December 2018 the average number of players was 395,509, marking a 27.55% increase from the month before. Also, in terms of peak concurrent users, in December this was 746,548, a big difference from November's 546,031.
If you bought CS:GO before it went free-to-play, your account will be upgraded to Prime status, if you weren't aware. This adds additional benefits like separate matchmaking, special weapon skins, and so on, and you can even buy Prime status if you don't already have it.
Have you jumped into CS:GO now that it's free-to-play?