American Gaming Association CEO Bill Miller told attendees at the Global Gaming Expo in October that the nation’s legal casino industry misses out on some $300 billion that gamblers wager annually with illegal betting operations.

He was off by more than $200 billion.

The Washington, D.C., trade group released a study last week that found Americans gamble an estimated $511 billion annually with illegal online sportsbooks and internet casinos, and unregulated slot machines.

According to the study conducted by The Innovation Group, the illegal operations cost the gaming industry $44.2 billion in potential gaming revenue – nearly half of the combined $92 billion produced by legal commercial and tribal casino operations in the United States last year.