These are the odds of who will win the 2016 election

Sen. Marco Rubio (R-Florida) isn't just surging in the polls. Gamblers are also increasingly putting their money on him to win the 2016 presidential race.

Business Insider got updated odds on the election from Paddy Power, Ireland's largest bookmaker, on Tuesday. As she was about a month ago, Hillary Clinton is still the overwhelming favorite. However, a few other candidates have seen their odds change.

Since launching his White House bid on April 13 and gaining ground in the polls Rubio has been popular with gamblers, according to Paddy Power spokesman Rory Scott.

"Betting has picked up on him, particularly in the last few weeks since he announced," Scott said of Rubio.

The odds for the rest of the GOP field are similar to where they were last month. However, New Jersey Gov. Chris Christie (R) has seen his standing drop. Scott said few people have been putting their money on Christie.

"Only 2 bets on him in the last 6 weeks!" Scott declared.

Christie has been facing a tumbling approval rating in New Jersey and looming reports of indictments in the so-called "Bridgegate" scandal that has rocked his administration.

On the Democratic side, Clinton's odds have remained steady. But Scott said two of her challengers have seen their chances improve.

Maryland Gov. Martin O'Malley (D), a likely opponent for Clinton, has seen his odds roughly double since last month. Scott also said Sen. Elizabeth Warren (D-Massachusetts), who is often mentioned as a potential candidate though she has repeatedly denied any intention of running, is the "fourth most backed selection" in Paddy Power's market for the 2016 field.

While both O'Malley and Warren are still far behind Clinton, Scott pointed to Paddy Power's odds from the 1992 presidential election cycle as a warning it might be too early to rule anyone out. At this point in that race, the eventual loser, former President George H.W. Bush was the favorite. The winner, Clinton's husband, former President Bill Clinton, was approximately where both O'Malley and Warren are now.

"I've checked what we were offering on Bill Clinton in April 1991. He was a 25/1 shot! He hadn't declared and there were only rumors about him standing," Scott said. "Bush was the short priced favourite. Betting is easy in retrospect!"

Check out Paddy Power's general election odds below.