New Jersey's nascent sports-betting industry reported $24 million in gross revenue in September, more than double the previous month, a surge boosted by the opening of the NFL football season.

New Jersey's sports-betting operations, which launched in June after the U.S. Supreme Court declared a federal ban on sports betting unconstitutional, already account for 8.5 percent of the state's total gaming revenue, according to monthly statistics released Friday by the New Jersey Division of Gaming Enforcement.

Gross revenue is roughly a measure of the amount of money wagered, minus the amounts paid back to winning bettors. Overall, sports-betting operators paid out $92.10 to winners for every $100 bet.

The sports-wagering tally was highly anticipated after David Rebuck, the division's director, told an industry conference in Nevada this week that the numbers would be "stunning."

"Driven by the explosive growth in sports wagering and continuing improvements in internet gaming and brick-and-mortar casino win results, the gaming industry produced another month of superb revenue increases," Rebuck said in a prepared statement. "The revenue results point to a strong finish for New Jersey's gaming industry in 2018."

Total gaming revenue for September — including casinos, internet revenue, and sports betting — was $281.7 million compared to $235.8 million last year, a 19.5 percent increase.

For the first nine months of this year, the industry's total revenue was $2.148 billion, up 5.4 percent over the same period last year.

Sports-betting revenue in September nearly equaled the $25.8 million taken in from internet gaming, which has grown steadily since its 2013 launch.

In four months, bettors in New Jersey have wagered $328.3 million on completed sporting events, losing $26 million, or 7.9 percent, to legal bookmakers.

Bettors wagered almost $119 million on baseball games, with bookmakers  keeping 3.5 percent of that in gross revenue. Football games attracted $94.5 million, and casinos retained 10.2 percent in winnings.

The big winner in September was Resorts Digital Gaming LLC, the online wagering unit of the Resorts Casino Hotel, which won $8.5 million in gross revenue from sports betting. The Meadowlands Racetrack LLC, which operates the closest legal sportsbook to New York City, collected $7.2 million in winnings, including nearly $2.9 million online.

The state collected $23 million in taxes on all gambling in September.