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The cumulative odds on this site add up to larger than 100%.

We're already at greater than 100% (106.5%). And there are 13 more cities with >= ~5% chance. It's pretty tough to have any faith in this site or their odds.

Could've been an interesting data point to look at though.

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Bookies have to eat. They are never going to give perfectly fair odds because then they don't make any money.

Also NB: The odds don't reflect the bookie's opinion of what the real outcome will be. They reflect the bookie's opinion of gamblers' willingness to bet on each option. The bookie is trying to get the odds-adjusted amount bet on each option to be as close to equal as they can manage. That way, no matter what the outcome is, they can just take the money paid by the losers give some of it to the winners and then keep what is leftover for themselves.

Yes, that's standard and it's called overrounding. If the odds were to sum to 100% then the bookmaker would make no profit. Betting exchanges such Betfair have books closer to 100%.

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