Roughly $4.76 billion will be wagered on Super Bowl 52 between the Philadelphia Eagles and the New England Patriots.

Some 97 percent of that $4.76 billion, or approximately $4.6 billion, will be wagered illegally.

The aforesaid figures are provided by the American Gaming Association (AGA), a national trade group representing the $240 billion U.S. casino industry. Every year, the AGA reveals its estimate of illegal wagering surrounding the Super Bowl.

The analysis is an inexact science. The AGA uses an old study--the 1999 National Gambling Impact Study Commission's Final Report--as a basis for its prediction. It takes the most conservative estimate of illegal sports betting from that study ($80 billion per year) and has applied gross domestic product (GDP) growth as reported by the Bureau of Economic Analysis to make it current in 2017 dollars.

Additionally, the AGA believes that the proportion of legal gambling activity on the Super Bowl at Nevada sports books is a good indicator as to what proportion it may make up in the illegal market.

The bottom line is that even if the AGA's figure is off, it serves as an important tool to remind the general public that, despite laws intended to prevent sports betting, wagering continues to occur on an annual basis, and particularly surrounding important sporting events such as the Super Bowl. Certainly, billions of dollars are wagered illegally, even if it is not necessarily nearing the $5 billion mark as the AGA suggests.

"Thanks to the failed federal ban on sports betting, Americans are sending billions of their hard-earned dollars to corner bookies, shady offshore operators, and other criminal enterprises," says AGA president and CEO Geoff Freeman. "The big question we're asking: Is 2018 finally the year when governments, sporting bodies, and the gaming industry work together to put the illegal sports betting market out of business?"

It may not even require that joint coalition to make a move toward curbing the illegal activity. The U.S. Supreme Court will soon rule on Christie v. NCAA, which could lead to a declaration that the federal sports betting ban (excluding Nevada) is unconstitutional, allowing states to adopt their own respective sports betting laws.

If the federal sports betting ban goes down, it still may not completely cripple the underground market, but you better believe that the AGA's yearly analysis on illegal sports betting surrounding the Super Bowl will need to be adjusted.