Well, nothing is so surprising about the USA leading gambling in every category. As we can all see, sportsbook, odds, spreads, and other sports betting related terms are what the sports casters talks about every single game. Even the commercials, casinos are always present. They are even a huge sponsors in mini games happening during timeouts and halftime.
However, I was expecting some countries in Europe would dominate the top 5. Looks like they're the kind of luxurious gamblers or maybe I'm just stereotyping here lol.
USA is surely one of the biggest market in many things so if they are also ruling in gambling it's not surprised, but few other countries are surprising even they are doing strict policies for controlling, but it's not helping, and their turnover is increasing.
Many countries those are had ban on this also have the good number of gamblers which are giving their contribution, but It's not officially so no one can give how much is going to online sites through them because I personally feel figures could be surprising because numbers are surely too much which are shown in above post.
India is also one of the country where things are going on new levels but due to policies nothing is officially same happening about few other countries those are fighting hard to stop this, but It's still having his share in their market.