The United States is not in this ranking, probably because it has a very large population and the ranking is based on the average loss per citizen of the country. Therefore, the total losses of US citizens must be huge to be in this ranking. UK may be in 11th or 12th place, who knows, unfortunately we only see the top 10 places.
I think you are mistaken here. The ranking is not based upon the loss but it is based on "Countries That Gamble The Most" and in this case US should be on top of the list. I think we should double check from another source too to check if the information provided by the site is authentic or not.
You say we need to double check the information but you haven't even read the article we're discussing, hehe. Here is a quote from the article:
Whenever gambling is mentioned, the glitzy images of Les Vegas come to mind. America has been considered as a gaming nation for a very long time. However, America is not the world’s biggest gambler as many would think. In fact, the biggest gamblers in the world include countries that are least suspect. The ranking of the 200 gambling countries is based on data provided by H2 Gambling Capital. The ranking takes into account the losses in a year divided by the adult population. The losses include the entire amount lost on all types of gaming including poker, slot machine, horse racing, and casinos.
sourceAs you can see, the calculation is done exactly as I said. And it is even emphasized that despite the image of the United States, it is far from the top of the most playing countries. By the way, I would like to know your version of the calculation of this rating - by what method should it be done and why do you think that the USA should be in the top?