The economy and the expansion of gaming in Pennsylvania continue to have an impact on Atlantic City's casinos.

Monthly revenues reported today by the New Jersey Casino Control Commission show that the seaside resort's 11 gambling halls had a 15.4 percent decrease in revenue last month compared with a year ago.

The casinos reported $351.3 million in total gambling revenue, down from $415.4 million in May 2008.

Slot machine revenue fell 14.9 percent to $246.6 million, but remained Atlantic City's main revenue generator - making up 70 percent of last month's total revenue. Table games revenue, which made up 30 percent, slid 16.7 percent to $104.7 million.

Gaming analysts say the debut of the $743 million Sands Resort Casino in Bethlehem on May 22 gave Pennsylvania slots revenue a boost at a cost to Atlantic City.

The new casino draws heavily from New York and North Jersey, two key feeder markets for Atlantic City. About 45 percent of the gambling mecca's clientele come from there.

Sands Bethlehem, which had its official ribbon cutting yesterday, generated $10.7 million in gross slots revenue from May 22 to 31, averaging just more than $1 million a day.

Pennsylvania's eight casinos took in $178.4 million in gross slots revenue last month, up 17.9 percent from a year ago. PhiladelphiaPark Casino and Racetrack in Bensalem led among the state's slots parlors, with $32.8 million.

In Atlantic City, the top performing casino was the Borgata, at $62.3 million last month, down 3 percent from last year. It was followed by Harrah's Resort, at $43.5 million, down 8.2 percent, and Bally's at $43.4 million, an 18.3 percent decrease.

For the first five months of the year, the 11 Atlantic City casinos took in $1.62 billion, down 15.7 percent from the same period last year.

Contact staff writer Suzette Parmley at 215-854-2594 or sparmley@phillynews.com.