I first thought it's just a question of numbers - many more customers. Then I saw it's not exactly true.
Europe population in 2019 is estimated at 743 million, which accounts for 11% of the world's population.
North America 366,496,802
South America 431,998,475
Central America 181,886,939
Too lazy to do the addition, but they seem to be a bit more? Not that much more, though.
Of course the question is not how many they are but how many of them watch Asian dramas.
Probably among US people and, even more so, Latin Americans, have more Asian drama fans?
I mean, they must have made their calculations based on some data, which we don't know.