SPRINGFIELD, Mass. (AP) — A Massachusetts casino reported its lowest monthly revenue in its 16-month history.

MGM Springfield's December gross gambling revenue was $18.9 million, down from $21.6 million a year ago. The Massachusetts Gaming Commission released its monthly numbers Wednesday.

The new numbers come amid concerns that MGM Springfield is losing out to an over-saturated gaming market and legalized sports betting opportunities in New York and New Hampshire, MassLive.com reported.

Overall, MGM has fallen short of promised revenue prior to its opening in August 2018. Regulators were told the casino would bring in an average of $34.8 million a month. Instead, the average over the first 16 full months was $21.54 million a month, with a high of $26.9 million in September 2018, its first full month of operations.

The president of MGM blamed the December numbers on the bad weather, though Encore Boston Harbor, another casino, reported an improvement in its gaming numbers from $47 million in November to $54 million in December.

Slots-only Plainridge Park Casino was $10.2 million in December, down a bit from $10.9 million in November. Year-over year, Plainridge was also down from $14 million in December 2018.