The number: $2.3 billion.
That's how much Nielsen says a fully mature U.S. sports gambling market could be worth annually to the NFL.
The report, released Wednesday, was commissioned by the American Gaming Association, the trade group that represents the gambling business.
The projections are based on a survey of fans. It assumes that regulated betting across America will boost media rights fees due to increased interest in the game, sponsorship by betting operators of teams as well as ancillary advertising, as well as the purchasing of official data from the league.
A nationwide, legal sports betting product available to all would affect annual media rights fees by nearly 18 percent, sponsorship by more than 7 percent and ticket sales by more than 6 percent.
Nielsen's report does not factor in so-called "integrity fees," where the league -- and perhaps the union -- would get a cut of the handle of what is bet on NFL games. The AGA has staunchly opposed such a model.
"So much time has been spent on talk over integrity fees," said Sara Slane, the senior vice president of public affairs for the AGA. "We think these numbers are conservative and show that the league is frankly tripping over dollars to pick up pennies."
Annual purchasing of league data, mostly for live in-game betting, would result in $30 million a year in revenue to the league, the report projects. The AGA isn't opposed to the idea of betting operators purchasing the official league data, as it helps increase speed from the action on the field to the operator, but the organization is opposed to the idea of being forced to buy league data.
In a memo sent to teams obtained by ESPN in July, the NFL wanted to force any casino brand that advertises with an NFL team to buy official league data.
There's a long way to go until the sports betting market is fully mature. Since the Supreme Court nullified the Professional and Amateur Sports Act of 1992, which then allowed states to make their own sports gambling decisions, four states have opened up to sports gambling: Delaware, New Jersey, West Virginia and Mississippi.