In theory, national gaming should have down more than 2 percent during September, according to Reno-based gaming analyst and consultant Ken Adams.

Instead, the month recorded a 4 percent increase.

Adams said new casinos in several states and the introduction of legal sports betting to four states reversed any trend that would have normally been impacted by an adverse calendar.

Instead, combined gaming revenue in the 21 states charted by Adams for the Adams Revenue Revue, was more $3.83 billion in September.

“Overall, gaming revenue changes are really being driven more by internal forces than external ones,” Adams wrote in the revue, which he produces for CDC Gaming Reports. “Absent a major economic reversal, the industry is in a very strong position right now.

Only four states saw dips in their monthly gaming revenue figures, the largest belonging to Indiana, down 10 percent. However, several states – including those with a significant video lotter presence – saw double-digit gaming revenue growth.

Legal sports wagering was the key factor for several states, including New Jersey. The market also benefitted from online gaming statewide and two new casinos in Atlantic City, pushing the state’s total gaming revenue up 20 percent.

Adams said casino revenues in Atlantic City were up 7.7 percent to $232 million, online gaming was up 26.3 percent to $25.8 million, and sports betting added another $24 million.

“Atlantic City is certain to report total revenue increases until the two new casinos and sports betting pass their first anniversary,” Adams said. “And it is just as likely that the existing casinos will struggle to match revenues of the previous year. The only outlier in that narrative is the continued growth of online gaming.”

Adams said new casinos in Maryland, Massachusetts and New York helped grow revenues on those East Coast state. The dominate force in Maryland has been MGM National Harbor, which will celebrate its second anniversary in December. During September the casino grew gaming revenue 10.3 percent, which fueled the state’s 6.9 percent increase.

With the first full month of results from the $960 million MGM Springfield, Massachusetts gaming revenue rose 176.5 percent to $41.2 million. New York’s combined VLT and casino revenue rose 9.1 percent to $219.0 million.

Another state Adams highlighted was Ohio, where gaming revenue from its four full-service casinos and seven slot machine-only race track casinos increased 4 percent. Casino revenue was down less than 1 percent, but race track casino revenues increase 8.1 percent.

The Cleveland-area Hard Rock Rocksino, which since been acquired by MGM Resorts International, grew gaming revenue 12.3 percent in September.

Meanwhile, sports betting is no longer exclusive to Nevada. In September, Nevada and four states – Delaware, New Jersey, Mississippi and West Virginia – combined to accept $817.17 million in wagers, with revenue of $95.5 million, which amounted to a hold of 11.6 percent.

“Don’t expect that win percent to become the norm, but it was a nice touch for the ongoing entrance of sports betting onto the national stage,” Adams wrote.

In the six months since the Supreme Court overturned federal law prohibiting single game sports betting, it has been a rush to the starting line. In addition to the first four states to join Nevada, a New Mexico Indian casino has added sports betting, and Rhode Island and Pennsylvania are expected to launch by the end of the year.

Close to a dozen other states are considering legislation to legalize the activity.

“By next year this time we probably will be looking at a whole new game, sports betting-wise,” Adams wrote.

CDC Gaming Reports distributes the Adams Revenue Revue to premium subscribers.

Howard Stutz is the executive editor of CDC Gaming Reports. He can be reached at hstutz@cdcgamingreports.com. Follow @howardstutz on Twitter.