The start of the pro football season, including a 3-0 start for the Denver Broncos, helped lift Colorado sports betting to a record $408.3 million in September, the Colorado Division of Gaming reported Friday.

Last month’s total was nearly double the total from either the month before or the year before. It beat the previous record set in January, during the NFL playoffs, by more than $80 million.

Nearly a third of the September total, $125.8 million, was bet on NFL football, which opened its regular season Sept. 9. The Broncos were undefeated in September but haven’t won a game since.

“NFL betting was by far the driver in the month,” Ian St. Clair, an analyst for Play Colorado, which tracks regulated gaming in Colorado, wrote in a commentary posted Friday.