Worldwide digital game sales reached nearly $10 billion across console, mobile and PC in December, according to SuperData Research’s monthly digital game sales report highlighting the purchasing trends outside of physical copies sold. Game sales grew 17 percent year-over-year, and revenue for the entire holiday quarter increased 19 percent from 2016.

SuperData Research attributes December growth to an increase in premium PC, console and mobile game purchases.

Nostalgia Wins Big

Call of Duty: WWII had the best quarter of digital unit sales ever for a console title, launching as the number one console game for December.

“This was the right time to return to the series’ original World War II setting,” Carter Rogers, senior analyst at SuperData, told AListDaily. “Gamers were getting tired of each successive entry going further into sci-fi territory, culminating in relatively poor sales (for a Call of Duty game) of Call of Duty: Infinite Warfare. For longtime fans, Call of Duty: WWII was a nostalgic return to form. For many younger gamers, this was their first WWII shooter, since the last major WWII Call of Duty released in 2008.”

Still Stealing The Spotlight

Grand Theft Auto V set another record month in December, SuperData reported. With the release of its “Doomsday Heist” update, GTA V Online broke its previous revenue record back in June 2017, making it the title’s best month to date for its multiplayer segment. Users reached 22.7 million across console and PC in December—the highest player numbers for the game since 2013.

Player Well-Known

Microsoft launched a port of Playerunknown’s Battlegrounds (PUBG) onto Xbox One consoles in December, and players responded by purchasing over two million digital copies. The game holds the number five spot on PC and number three for digital console sales in December.

PUBG has spawned a popular new genre much in the way that Doom spawned first-person shooters. Inspired and named after the 2000 film Battle Royale, this free-for-all game mode pits massive amounts of players against one another—up to 100, in the case of PUB—and the winner is the last one standing.

Other game publishers are riding the battle royale wave of success, including mobile PUBG clones Knives Out and Rules of Survival—each experiencing successful launches in December.

The biggest competitor to PUBG is currently Epic Games’ Fortnite Battle Royale, which earned $89 million in December. Epic Games’ entry into the Battle Royale arena continues to gain traction with gamers, but at the expense of its massive online battle arena (MOBA) title, Paragon.

Fortnite‘s success will certainly be Paragon‘s loss,” Rogers explained, and also mentioned Epic has moved some staff from Paragon to support Fortnite, as the former made $862,000 in December, while Fortnite earned $89.1 million. “[So] Epic has a good reason for doing this. Paragon has never been able to break into the top tier of MOBAs.”