Despite efforts from both Valve and legal entities to slow the momentum of online gambling sites that revolve around betting Counter-Strke: Global Offensive skins, nearly $5 billion was wagered on skins in 2016 alone—according to a recent ESPN feature.

The ESPN piece is a powerful breakdown of both the history and ongoing ethical issues surrounding the illicit Counter-Strike online gambling world, all of which is made more striking by the sheer amount of money that continues to circulate through numerous betting sites.

The feature cites research from Eilers & Krejcik Gaming and Narus Advisors that states about 40 percent of the $5 billion worth of skins wagered last year were bet on the outcomes of eSports matches and tournaments.

The remainder of the bets, roughly $3 billion, are funneled into more traditional online gambling sites that accept wagers on slots, roulette games, dice rolls, or coin flips.

The story alleges that Valve’s open API is largely responsible for the ease at which children are able to participate in these online gambling sites that substitute betting chips for Counter-Strike skins. A similar sentiment has been shared by the Washington State Gambling Commission in the past, which ordered Valve to stop facilitating the use of skins as gambling currency.

Valve itself has said it has taken steps in the past to discourage such gambling activities, including disabling Steam accounts known to associate with such websites and sending out cease and desist letters to many known betting sites, but for the most part the company maintains that it has no relationship with the sites that profit off of unregulated Counter-Strike skin trading.