There are many multi-billion dollar markets throughout the world, but perhaps few are as burgeoning as the sports betting business. The amount of money placed on sports wagers each year continues to balloon, and with Super Bowl 50 about a week and a half away, that's not going to change.

Last year's Super Bowl matchup between the New England Patriots and Seattle Seahawks saw an estimated $3.9 billion in wagers, but this year's game is expected to surpass that.

"According to an estimate released today by the American Gaming Association (AGA), Americans will bet $4.2 billion on Super Bowl 50 between the Denver Broncos and Carolina Panthers, up eight percent over last year," according to an AGA press release.

However, sports wagers can only be placed legally in few places throughout the United States, so an overwhelming majority of the wagering will take place on the black market.

"Nearly 97 percent of those bets - $4.1 billion worth - will be wagered illegally, standing in stark contrast to the approximately $115 million bet legally on the New England Patriots-Seattle Seahawks game last year. In fact, the illegal market is 35 times greater than the legal marketplace."

Not only that, but the AGA's estimate determined $149 billion was wagered on sports in the United States in 2015, which was up about $4 billion from the previous year.

Last year the AGA released its first-ever estimate on Super Bowl wagers and projected $3.8 billion in illegal bets. This year they estimated the total amount of money in both legal and illegal wagers.

However, this also could be a record-setting year for legal bets. Super Bowl XLVIII between the Broncos and Seahawks set a record with $119.4 million in wagers, but Vegas sportsbooks are anticipating more action for the Broncos/Panthers matchup.

"It's an event that really reflects the popularity of the sport and the strength of the economy," Jay Kornegay, who runs the Westgate Las Vegas Superbook, told The Associated Press. "We expect this to be a record setting year for the Super Bowl."

Check out HNGN's betting guide for Super Bowl 50 here.