Global free-to-play games revenue saw a 6 percent increase to $87.1 billion last year, with Epic Games' Fortnite ($1.8 billion), Nexon's Dungeon Fighter Online (1.6 billion) and Tencent's Honor of Kings ($1.6 billion) ranked in the top three spots, according to a recent report from data analytics company Nielsen's SuperData Research Group.

Chinese internet giant Tencent also saw its Game for Peace ($1.2 billion) and co-published League of Legends ($1.5 billion) among the top 10 list.

Last Shelter: Survival, which was produced by Beijing-based Long Tech Network Limited, took the 10th place with $1.1 billion in revenue.

According to the report, world digital games revenue last year had a 3 percent year-on-year rise to hit $109.4 billion, among which free-to-play games spending accounted for 80 percent of all the revenue, thanks to strong performances from mobile games.

Chart-topping regulars like Honor of Kings and Candy Crush Saga promoted mobile's share of free-to-play income to 74 percent, said the report.

Besides, mobile games accounted for six of the top 10 free-to-play games by revenue, the report showed. Last year, mobile games earned $64.4 billion.

The premium games market, however, saw a 5 percent decrease last year to $18.9 billion, since there were fewer blockbuster games launched than the year 2018, the report said.